Lady Gaga has admitted that she used to fantasise about lesbian sex when she was in a relationship with her ex-boyfriend.

The star, who has admitted to having sexual relations with women in the past, made the revelations in an interview with US chat Queen Barbara Walters.

Asked by the talk show host whether she had had sex with women, a squirming Gaga responded: "Um, uh... well I... my goodness! I have certainly had sexual relationships with women, yes.”

According to The Sun, she added: "I do like women. I've only been in love with men - I've never been in love with a woman.

“That's what 'Poker Face' was all about... Why, when I was with my boyfriend, was I fantasising about women?

Gaga – real name Stefani Germanotta – was being interviewed as part of an ABC TV special about 'The 10 Most Influential People of the Year'.