WATCH: Gene Simmons and Ace Frehley perform together for the first time in 16 years

The former band mates united at The Children Matter Benefit Concert at the 10,000 capacity CHS Field Stadium in St. Paul, Minnesota, which was held to raise money for the victims of Hurricane Harvey.

Ace appeared on stage during the Gene Simmons Band headline slot and the pair shared vocal duties on three classic KISS tracks from the seventies; ‘Parasite’, ‘Cold Gin’ and ‘Shock Me’.

Watch footage of all three songs here:

Other performers at last night’s charity concert included former Eagles guitarist Don Felder and Cheap Trick.

Gene and Ace last played live together at the Carrara Stadium in Queensland, Australia in April 2001 on the swansong night of the KISS Farewell Tour.

Back in June of this year, Gene revealed that he has co-written two songs for Ace’s next solo album.

“Literally two days ago I was with Ace and we wrote two songs,” Gene told Minnesota radio station 92 KQRS. “He asked me to write for his next solo record. So I went over to his place, way out in the desert some place, and we wrote two things.”

Paul Stanley guested on Ace’s 2016 covers album ‘Origins, Vol.1’ on a reinterpretation of Free’s song ‘Fire and Water’.

Despite the former band mates being on good terms, earlier this year Paul categorically ruled out the idea of a KISS reunion with original members.

Asked if it could happen by Billboard, Paul said: “No. And that’s not coming from any place of animosity. I sang on Ace’s most recent album and did a video with him.

“I have the connection and the reconnection and to celebrate the good things we’ve done together is terrific. The band as it is—I’ve played with Eric Singer for I think 25 years and Tommy’s (Thayer) been in the band probably 15 years at this point.

“I have no thoughts of re-visiting the past. With that said I am happy to enhance or do whatever I can for anyone who has helped put me where I am, but that doesn’t include getting hitched again to somebody I unhitched from.”