The America's Got Talent judge dished about the Spice Girls' behind-the-scenes drama during a Wednesday night appearance on Watch What Happens Live.
Asked whether a fight between her and Ginger Spice caused Geri Halliwell to leave the band in 1998, she replied, "I don't think it was my feud. I think she had some stuff going on in her head."
"I don't think she could take the pressure," Brown, 39, told Andy Cohen. "She actually talked about it in her book, and she just bounced."
"But she happened to have left on my birthday," she added, joking, "What a b––––!"
Twenty years after the Brits shot to fame, the friends have mended fences, reuniting for a 2007 concert tour, performance at the 2012 London Olympics and plenty of fun nights on the town.
Though she counts Sporty Spice (Melanie Chisholm) as her best gal pal, Mel B said she's still close to all the singers, dismissing rumors of a rift with Victoria Beckham.
"They always say that. I think because we just get in fights every now and again, but then we always make up," she said of Posh.
One star she did have beef with? Hip-hop mogul Diddy, who dissed her at an awards show by yelling at her to get off the stage.
"Well, I said, 'Come over here and say that to my face," and then we got into a bit of a F-you scenario," she explained.
So did Scary Spice scare off Puff Daddy?
"Oh now, not I see him at SoulCycle and he's fine," she said, laughing. "He's like, 'Hey, Mel, how are you?' It's all cool."