Katie Holmes has been having the time of her life with a mystery man

In the city for her new play All My Sons, Katie's found time between rehearsals to sneak coffees with the stranger.

"Mr X, the crew call him," says a source. "Everyone knows that there's nothing romantic going on, but it's still got tongues wagging.

"One of the girls on the crew saw them having coffee last week, and when she went over and said hello ... even though they spoke for about five minutes, Katie didn't introduce the mystery man.

"She told me that he's a friend from LA who's in New York as well and they've just been catching up."

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