It was Fergie's first time in the clubhouse with Cohen and she, of course, had to play "Plead the Fifth."
The 42-year-old was asked about the "best and worst part of dating Justin Timberlake," of which she replied, "It wasn't all that serious." She then passed on further answering the question.
When asked about her favorite project that her estranged husband, Josh Duhamel, has worked on, Fergie revealed that it wasn't a movie or TV show but rather the jokes he makes on a text chain with his buddies.
Fergie also reacted to fans who believe that the chorus in Taylor Swift's new song, "Look What You Made Me Do," sounds strikingly similar to the Black Eyed Peas' 2005 hit, "My Humps."
The former Black Eyed Peas front woman didn't seem affected by the song comparisons and noted that her new track, "Just Like You," also has similarities to "LWYMMD."
She even pitched that she and Swift do a "three-way mashup" with their songs.
"Kim, I had more fun with on set, because we were on set, to be literal," she continued.
Fergie spoke to ET last week about how Jenner came to star in her music video. "We had this kind of random moment at Coachella, we ended up in this car ... going to this party," she recalled. "We're just in this car and we're playing music and the sun was going down ...I remember filming, she was lip-syncing to a song and I remember thinking, 'Wow, she has like an inner pop star inside of her.'"
As for Jenner's role in the music video, Fergie added, "I just wanted her to do her and she did. She did, she rocked it out."