The 44-year-old star, who appeared on "Jimmy Kimmel Live!", added the situation was a little "tricky" as her former partner and actor Micheal Sheen is currently in a relationship with Kimmel's ex-girlfriend.
"You know how they have crushes on Justin Bieber and things like that? She's got one on you. It's a little bit of a tricky situation, because my daughter's dad is dating Jimmy's ex-girlfriend - it's very twisted. It's a sort of horrible, human centipede-y vibe," Beckinsale said.
The "Love and Friendship" actor's revelation left Kimmel a little red-faced, to which he said, "I'm sorry! I had nothing to do with this! This is all her! This is your mother! Let's not ruin the crush thing.