"Something magnificent has happened to me and something extraordinary, and I'm so happy I can't restrain myself," he insisted.
Cruise, 42, said Holmes, 26, was arriving in Berlin later Tuesday for an event the next day to publicize her movie Batman Begins.
The pair is due to travel together on Wednesday to Rome, where they were first photographed together in April, the Associated Press reports.
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As for his own movie, Cruise gave it the thumbs up, saying at the premiere: "It's just a great story, I remember being a kid growing up and hearing about the H.G. Wells radio play and the effect that that had on society."
The 1938 radio production by Orson Welles of the H.G. Wells novel about an alien conquest of New Jersey was so realistic that a widespread panic broke out around the country. In the new movie, directed by Steven Spielberg, Cruise plays a father trying to save his children from the alien invasion.