Former X Files stars David Duchovny and Gillian Anderson have reunited for an onstage duet that was more like The X Factor.

They sang together in New York City, performing Neil Young's Helpless on the day Duchovny released his first album.

The Golden Globe-winning actor sang lead while Anderson harmonised with his backing singers and band.

"Can we play some real music please?" Anderson joked, joining in when Duchovny and his band returned for an encore performance at The Cutting Room.

"Is there anything you're in the mood for perhaps?" the actor asked the actress, who replied: "Do you guys know Helpless?"

Duchovny gave Anderson a light kiss on the lips after the performance and whispered in her ear as she left the stage.

The musical collaboration comes ahead of the duo reprising their roles on The X Files for a six-episode run this summer. The hit series lasted nine seasons after launching in 1993.

Duchovny sang songs from his debut album, Hell Or Highwater, and was backed by a full band. The disc features 12 tracks he wrote.

Anderson was not the only co-star to join him onstage: Madeleine Martin, who played Duchovny's daughter on the TV series Californication, sang the new album's title track with her TV father.

The crowd at the intimate show was enthusiastic for the actor's 90-minute performance.

"I made the mistake of wearing a sweatshirt," he said of the warm room as fans whistled and yelled: "Take it off!"