Brown, 39, was chatting with Cohen, 46, to promote America's Got Talent, but also took the time to reflect on her years as Scary Spice.
For much of the late '90s, Brown famously performed with Victoria Beckham, Emma Bunton, Melanie Chisholm, and Geri Halliwell, creating a group dynamic of five good friends. She was asked by a caller on WWHL, however, which of her bandmates is her closest confidante.
"I'm kinda close to all of them but I think it would have to be Mel C cause she's from up north, where I'm from," she answered of Sporty Spice.
After squashing rumors that she and Beckham are not close, Brown addressed Halliwell's departure and the Spice Girls' split. There were rumors at the time that Ginger Spice departed because of bad blood with Brown.
"I don't think it was my feud," the America's Got Talent judge told Cohen. "I think she had some stuff going on in her head… I don't think she could take the pressure. She actually talked about it in her book and she just bounced. But she happened to have left on my birthday. What a bitch!" she joked.
The former pop idol was then put in the hot seat for a round of WWHL's "Plead the Fifth" segment, where guests are asked three tough questions and allowed to pass on only one. Brown pled the fifth on the question of which Spice Girl was the least vocally talented.
While she originally passed on the question of which Spice Girl hooked up with the most fans, she circled back to it, naming herself while adding that hooking up could mean going on "dinner dates."
Finally, Cohen asked Brown, "Name one celebrity that was a huge d--k to you during your Spice Girls days."
Lamenting the difficulty of answering the questions, Brown finally said, "I did have an argument Puff Daddy, I did… He yelled at me to get off the stage when I was hosting this awards show… I said, 'Come over here and say that to my face' and then we got into a bit of an 'f you' kind of scenario."
The tension didn't continue into the rapper's P. Diddy days and Brown's post-Spice Girls life, however. "Now I see him at SoulCycle and he's fine!" she said. "He's like, 'Hey Mel, how are you?' It's all cool."