And Cruise's behavior prompted Winfrey to exclaim repeatedly: "You're gone!"
"I've known Tom a long time and he has always been so private. I've never seen him like this before – he's gone," Winfrey said. "You are just out everywhere, kissin' and huggin'. And I thought, What has happened to you?"
Cruise, who spent much of the interview pumping his fist, jumping onto Oprah's couch and laughing with embarrassment about the subject, gushed: "I'm in love. And it's one of these things, where it's like, you know, you wanna be cool....That's not me... I admired her and I thought I wanted to meet her. And I called her. … She's an extraordinary woman."
Oprah then asked: "Does that mean you're going to ask her to marry you?"
"I gotta discuss it with her," he replied, smiling.
More on Tom & Katie
At the end of the show, Oprah said she knew Holmes was in the building, and after leading the audience in a "Ka-tie!" chant to have her come out, Cruise went backstage and retrieved her himself.
When asked whether she envisioned she'd be dating the actor after admitting that her childhood dream was to marry Cruise, Holmes replied: "I'm glad I was a big dreamer."
Cruise, 42, and Holmes, 26, have only been dating for a few weeks, but the pair have been far from private about their blossoming romance. The pair first went public in Rome last month, and most recently they joined Winfrey at her 42-acre estate near Santa Barbara, Calif., for the talk-show queen's Legends Ball.
Cruise split with girlfriend Penelope Cruz last year. He and Nicole Kidman, who have two adopted children, divorced in 2001. He was previously married to Mimi Rogers. Holmes, meanwhile, split with fiancé Chris Klein in March.
Both Holmes and Cruise have big movies opening this summer. Hers is Batman Begins, and his is Steven Spielberg's War of the Worlds.