The X Factor judge, 39, is now happily married to film producer Stephen Belafonte, but told The Guardian Weekend that prior to that she fell in love with a woman who had children at the same school as she did.
"I did have a four-year relationship with a woman," said Mel, cheekily adding: "But I've been very happily married for seven years to a penis. Ha ha! An amazing guy!"
Mel – who has three children – went on to say: "I've definitely not been shy or been one to hold back. If I wanted to try something, I did. I had a girlfriend. So what?"
She declined to reveal the woman's identity.
The former Spice Girl also took the opportunity to rubbish rumours that she and husband Stephen enjoyed an open relationship, saying: "No, me and my husband are very tight and solid."
However, she added: "But I will be the first one to compliment a woman, to say to my husband, 'Oh my God, look at her legs', or, 'Doesn't she look stunning?' I do think women are gorgeous. Crazy but gorgeous."
Mel is mum to daughters Phoenix, 15, Angel, seven, and Madison, three.
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