"When I first met him, he didn't want to do anything that made him look silly," Schwimmer, 23, tells PEOPLE of her "shy" dancing partner, 42. "Now he's all for it. He's goofing off and he's pretending to be Maks [Chmerkovskiy] in rehearsals. It's really funny."
Schwimmer, who acknowledges that she and her partner are the "underdogs" this season, says people might be surprised how quickly Bono is whipping into shape.
"He's lost five pounds in six days," she says. "It's so great. He says he's not eating any differently, he's just dancing." Part of Bono's ease during practice likely comes from how well he and Schwimmer mesh.
"He's such a great guy," the professional dancer says. "He is so nice, and he's such a kind person. He's awesome. I couldn't have asked for a better partner this time."
Despite breaking out of his shell, there's something Bono still adamantly requests not to do on the show.
"Chaz has already told me he doesn't want to dance to any of his parents' songs," Schwimmer says of Bono's iconic singing mom and dad duo, Sonny and Cher. "But the show really wants it to happen, so we'll see."
Whether or not Bono and his partner will waltz across the ballroom to "I Got You Babe" remains a mystery, but Schwimmer does say there's a chance that her partner's famous mom will have some a presence on the show.
"Rumor has it that Cher wants to come to the show," Schwimmer says. "So I hope that's still in the works. I'd love to meet her."