Lady GaGa wanted to be known by a different name during her time on set filming 'Joker: Folie a Deux'.

The pop star - who was born Stefani Germanotta - plays the Joker's henchwoman Harley Quinn in the new movie opposite Joaquin Phoenix as Batman's nemesis and now cinematographer Larry Sher has revealed the singer stayed in character when the cameras weren't rolling and wanted to be called Lee.

Speaking on 'The Trenches TV' podcast, Sher explained he struggled to bond with the leading lady until he found out he had been calling her the wrong name. He explained: "I feel like I never really even met her, even during the make-up hair test. Because, again, maybe it's my philosophy of never trying to get in their space.

"And then I remember for like a week being like, "God I feel like we were disconnecting, not even connecting. We’re like on opposites'. And I would say to my crew like: 'Jesus I can’t crack it. I feel like she either hates me or we hate each other or there’s something weird going on here'."

However, it all changed after he was clued into what the singer wanted. He added: "Then the AD [assistant director] at one point said: 'Oh you know Stef would like if you just called her Lee on set'.

"And I was like, ‘Oh, 100 per cent.’ And then I literally said like the next thing I said was something Lee, and it was like everything changes.

"From that point on it was like our whole connection changed. I was like, OK cool, that's all I needed to know."

Lady Gaga's co-star Phoenix is known for staying in character while working on films, but Sher revealed the actor approached him on the second day of the shoot and explained what was going on.

He said of the Oscar-winner: "[Phoenix said sorry] for being whatever like weird, I just need to stay[(in character]."