The 41-year-old actress and 45-year-old television personality recalled on Monday's episode of The Tonight Show starring Jimmy Fallon how they almost dated on the set of the film Almost Famous.
Hudson and Fallon played Penny Lane and Dennis Hope, respectively, in the 2000 movie. Hudson said she recently reminisced about her time on set.
"I was going through all the memories. I was like, 'Oh my God. This was this most magical moment.' Do you remember how much fun we all had?" Hudson asked Fallon. "And then you and I ended up hanging out all the time."
Fallon was playing a game with Margot Robbie on The Tonight Show in December when he named Hudson as a co-star he thought he could have dated but didn't. On Monday, Hudson said she had "no idea" Fallon was interested.
"Like, I wish people could be in my body to watch you and I's relationship and friendship, because you gave me no indication," the actress said.
"Jimmy, if you would have actually made a move I would have totally gone there," she added. "I remember thinking to myself, 'Why has Jimmy never made a move?' Then I just kind of realized, 'Oh, he's not into me like that.'"
Hudson and Fallon were seeing Kids in the Hall when Hudson met her partner Chris Robinson, a singer for the band The Black Crowes. Hudson has since split from Robinson but has a son, Ryder, 16, with the musician.
"Everything turned out perfect," Fallon said.
"Exactly like it was supposed to," Hudson agreed.
Hudson is also parent to a son, Bingham, 8, with Matthew Bellamy and a daughter, Rani Rose, 18 months, with her boyfriend, Danny Fujikawa. Fallon married Nancy Juvonen in 2007 and has two daughters, Winnie, 6, and Frances, 5, with his wife.