Singer/songwriter Bonnie McKee has opened up about her bisexuality, revealing childhood games made her realise she was attracted to both boys and girls.

MCKee, who has written hits for Katy Perry, Ke$ha, Carly Rae Jepsen and Britney Spears, hasn't spoken publicly about her sexual preferences before but the big reveal came about after she confessed to a crush on Justin Bieber in a recent interview with Joan Rivers.

She told the comedienne, "He's really pretty. He looks like a hot lesbian. I'm into that."

And when Rivers asked if she was bisexual, MCKee replied, "Yes, I am," adding, "I think it's one of those things where, you know, I think all little girls kind of play doctor with their girlfriends, and then I kind of never grew out of it."

The 30 year old, who has been dating producer Oliver Goldstein for seven years, shares a kiss with a female love interest in her music video for the song Sleepwalker.