This is coming as a bomb shell to the entertainment world.
Mel B has revealed she slept with fellow Spice girl Geri Halliwell.
Scary Spice, 43, claims the pair enjoyed a wild night of passion, which they “giggled” about afterwards.
And she laughed that pal Geri, 46, would “kill her” for finally spilling the details.
The singer made the shock revelation as she spoke to Piers Morgan for his new Life Stories series at a recording on Friday night.
She nodded after Good Morning Britain’s Piers asked: “Did you sleep with Geri?”
Geri is now married to mega-rich Red Bull Formula 1 boss Christian Horner and has two kids.
“She is going to hate me for this because she is all posh in a country house but it wasn’t a ‘thing’, it just happened, we just giggled at it and that was it,” she confessed. “We were best friends. It just happened.”
The admission even shocked Piers, who gasped: “This is a Spice Girls bombshell. You have never admitted this before, have you? People are going to be fascinated.”
Mel answered: “Yeah and I’ve said it now. She is going to kill me and so is her husband.”
“Well she is not that posh now is she?” Piers shot back, before asking if the Spice Girl on Spice Girl encounter “was good”.
There was a long silence from mum-of-three Mel before coughing from her family in the audience could be heard.
Her daughter Phoenix, 19, sister Danielle and mum Andrea were at the studio watching.
In the past, Mel has hinted at wild times with bandmates but would only say, “back in the day, I had fun”.
Another time, when pressed on if she’d bedded them, she said: “Do you mean sex, or did we just sleep in a bed together? Sex? Let’s just say I slept in a bed with them all.”
Mel and Geri have remained close friends and will be reunited for the Spice Girls tour later this year, minus Victoria Beckham.
Later in the interview with Piers, due to air this summer on ITV, she also admitted kissing Mel C.
But she insisted it was “nothing sexual” and just to test out her new tongue piercing.
And she also said she hoped Geri would not deny her revelation, saying “it was just a fun thing”.
Last year, Mel spoke out on her abusive relationship with ex-husband Stephen Belafonte in her book, Brutally Honest.