The girls, who picked up another BRIT Award last week, have joined the likes of Dani Dyer, Dan Walker, Ed Balls, Alexander Armstrong, Anita Rani, Osi Umenyiora, and Shirley Ballas to climb the 19340ft mountain in Africa, in an attempt to raise money for Red Nose Day.
And now, just days into the climb, Jade and Leigh-Anne have given fans an update, admitting it's been very 'tough'.
Taking to Instagram to post a snap of the mountain, the girls wrote, 'It’s been a tough couple of days!! But to see the summit of kili in front of us has given us the motivation to get to the top! We got this! #returntokili'. sic
The girls later posted a cute photo of themselves in their walking gear, simply writing, '⛰⛰⛰ #ReturnToKill'. sic
Fans of the 'Shout Out To My Ex' hit-makers were quick to comment on the updates, with one writing, '😍 you girls are awesome🙌🙌'.
Another added, 'YOU GOT THIS❤️', with a third adding, 'How do you do it to look so flawless even on a mountain hike??? I don't understand...'. sic
Check out Little Mix through the years:
2011
After being put into a group by Kelly Rowland on The X Factor in 2011, the Little Mix girls rocked denim and trainers as they posed at the Judges Houses' stage of the competition.
Little Mix update fans on 'tough' Mount Kilimanjaro climb
2 of 24
2018
The girls then changed into smart black and white suits for their first ever performance of 'Woman Like Me' with Nicki Minaj.
2011
After being put into a group by Kelly Rowland on The X Factor in 2011, the Little Mix girls rocked denim and trainers as they posed at the Judges Houses' stage of the competition.
2011
Throughout their time on The X Factor, Jade, Perrie, Jesy and Leigh-Anne stuck with the same 'colour and prints' theme for performances, each making an identify for themselves.
2011
Attending the Twilight Breaking Dawn Part 1 premiere in 2011 with their X Factor mentor Tulisa, the Little Mix girls dressed up in stunning LBDs.
2011
After winning The X Factor ahead of Marcus Collins, Little Mix started to make an identity as a band, co-coordinating their outfits both on stage and at events.
2012
One year on from their historic win on The X Factor, Little Mix returned to perform their brand new single, looking more grown up.
2012
At the launch for Little Mix's debut album 'DNA', Jade, Perrie, Leigh-Anne and Jesy looked stunning in black outfits.
2013
All of the Little Mix girls have experimented with their hair colours, but in 2013 Perrie went for purple, whilst Jade was rocking the colour blue.
2013
Attending their first ever BRIT Awards in 2013, Little Mix dressed up for the occasion, all wearing totally different outfits.
2013
Experimenting even further with her hair in 2013, Perrie changed her look from purple to dip dye pink later in the year.
2016
After taking some time off to work on their new album, Little Mix returned in 2016 with a brand new look. Looking a lot more grown up, the girls started to wear a lot more custom-designed outfits on stage.
2015
Perrie couldn't resist getting into the Disney spirit in 2015 when she made a trip to Disneyland Paris!
2016
Walking the red carpet ahead of their first ever BRIT Awards performance, Little Mix oozed glamour as they invited their mums along for the party.
2016
That same night the girls took to the stage in matching green and black outfits to give an incredible performance of their hit song 'Black Magic'.
2017
After receiving some harsh criticism online for some of the more risqué outfits, Little Mix wore suits for their performance of 'Power' during The X Factor finals in 2017.
2017
After taking more of an interest in fashion, attending various fashion events with her band mate Jade Thirlwal, Leigh-Anne started to take inspiration, wearing this cute number for her birthday in 2017.
2017
Little Mix embraced the race driving theme brilliantly in 2017 when they performed at F1 Live in London.
2017
The girls attended the Nickelodeon Kids' Choice Awards in Los Angeles in 2017, rocking the red carpet with their different outfit choices.
2017
Whilst Perrie, Jade and Leigh-Anne stuck with their natural hair colours in 2017, Jesy experimented a lot, even dying her hair bright pink!
2018
Looking completely stunning, Jade, Leigh-Anne, Jesy and Perrie rocked the red carpet at the 2018 BRIT Awards. Whilst most fans loved their look, Jesy, Jade and Perrie were quick to mock Leigh-Anne for wearing her 'dressing gown'.
2018
Little Mix stars Leigh-Anne and Jade attended The British Fashion Awards in 2018, wearing stunning dresses to the prestigious event.
2018
The girls went for a more retro look during a performance to their fans in Germany in 2018.
2018
At the launch of their amazing album 'LM5' in 2018, Leigh-Anne, Jesy, Perrie and Jade looked casual and chic as they signed copies of their album for fans.
2018
Ahead of their performance with American rapper Nicki Minaj, Jesy injected a bit of colour into Little Mix's red carpet look at the 2018 MTV EMA Awards, whilst Leigh-Anne rocked green dreadlocks.
2018
The girls then changed into smart black and white suits for their first ever performance of 'Woman Like Me' with Nicki Minaj.
2011
After being put into a group by Kelly Rowland on The X Factor in 2011, the Little Mix girls rocked denim and trainers as they posed at the Judges Houses' stage of the competition.
2011
Throughout their time on The X Factor, Jade, Perrie, Jesy and Leigh-Anne stuck with the same 'colour and prints' theme for performances, each making an identify for themselves.
2011
Attending the Twilight Breaking Dawn Part 1 premiere in 2011 with their X Factor mentor Tulisa, the Little Mix girls dressed up in stunning LBDs.
2011
After winning The X Factor ahead of Marcus Collins, Little Mix started to make an identity as a band, co-coordinating their outfits both on stage and at events.
2012
One year on from their historic win on The X Factor, Little Mix returned to perform their brand new single, looking more grown up.
2012
At the launch for Little Mix's debut album 'DNA', Jade, Perrie, Leigh-Anne and Jesy looked stunning in black outfits.
2013
All of the Little Mix girls have experimented with their hair colours, but in 2013 Perrie went for purple, whilst Jade was rocking the colour blue.
2013
Attending their first ever BRIT Awards in 2013, Little Mix dressed up for the occasion, all wearing totally different outfits.
2013
Experimenting even further with her hair in 2013, Perrie changed her look from purple to dip dye pink later in the year.
2016
After taking some time off to work on their new album, Little Mix returned in 2016 with a brand new look. Looking a lot more grown up, the girls started to wear a lot more custom-designed outfits on stage.
2015
Perrie couldn't resist getting into the Disney spirit in 2015 when she made a trip to Disneyland Paris!
2016
Walking the red carpet ahead of their first ever BRIT Awards performance, Little Mix oozed glamour as they invited their mums along for the party.
2016
That same night the girls took to the stage in matching green and black outfits to give an incredible performance of their hit song 'Black Magic'.
2017
After receiving some harsh criticism online for some of the more risqué outfits, Little Mix wore suits for their performance of 'Power' during The X Factor finals in 2017.
2017
After taking more of an interest in fashion, attending various fashion events with her band mate Jade Thirlwal, Leigh-Anne started to take inspiration, wearing this cute number for her birthday in 2017.
2017
Little Mix embraced the race driving theme brilliantly in 2017 when they performed at F1 Live in London.
2017
The girls attended the Nickelodeon Kids' Choice Awards in Los Angeles in 2017, rocking the red carpet with their different outfit choices.
2017
Whilst Perrie, Jade and Leigh-Anne stuck with their natural hair colours in 2017, Jesy experimented a lot, even dying her hair bright pink!
2018
Looking completely stunning, Jade, Leigh-Anne, Jesy and Perrie rocked the red carpet at the 2018 BRIT Awards. Whilst most fans loved their look, Jesy, Jade and Perrie were quick to mock Leigh-Anne for wearing her 'dressing gown'.
2018
Little Mix stars Leigh-Anne and Jade attended The British Fashion Awards in 2018, wearing stunning dresses to the prestigious event.
2018
The girls went for a more retro look during a performance to their fans in Germany in 2018.
2018
At the launch of their amazing album 'LM5' in 2018, Leigh-Anne, Jesy, Perrie and Jade looked casual and chic as they signed copies of their album for fans.
2018
Ahead of their performance with American rapper Nicki Minaj, Jesy injected a bit of colour into Little Mix's red carpet look at the 2018 MTV EMA Awards, whilst Leigh-Anne rocked green dreadlocks.
2018
The girls then changed into smart black and white suits for their first ever performance of 'Woman Like Me' with Nicki Minaj.
The trek, which is due to last around eight days, will see all of the celebrities pushing themselves to the limit on the 19,000ft peak. The climb will be filmed for a one-hour special which is set to air on the BBC for this year's Comic Relief.
It was way back in 2009 when Take That singer Gary Barlow got his celebrity mates together to raise a massive £3.5 million, with all of the celebs reaching the top, despite both Cheryl and Ferne Cotton collapsing in the process.
We wish them the best of luck! 💪
NOW WATCH: Mabel chats about Little Mix & Dua Lipa's performances at the 2019 BRITs
You can tune in to KISS FM UK and other KISS channels including KISSTORY, KISS Fresh, KISS Dance, Hip- Hop, Jams and more – all within the official KISS KUBE app (iPhone, iPad & Android).
