Tom Cruise and Katie Holmes Leading Separate Lives?

Tom Cruise and wife Katie Holmes are leading increasingly separate lives -- which is causing problems in their relationship, according to reports.

Katie, 29, is currently rehearsing in NYC for her Broadway debut in Arthur Miller's All My Sons. She flew into Los Angeles last week to attend the premiere of new comedy Tropic Thunder, in which Tom has a bit part.

At the after party, the Top Gun star -- who was his usual energetic-self -- worked the room. But Katie struggled just to stay awake.

A source tells Life & Style magazine, "She managed to smile, but she seemed really out of it.

"It just looked like she hadn't slept in a while."

The next morning, the former Dawson's Creek actress was back at rehearsal, having flown 3,000 miles overnight to NYC. After putting in a seven-hour workday, Katie changed and headed out yet again, this time joining her 2-year-old daughter, Suri, for an evening at NYC's Chelsea Piers gym complex. While Suri happily bounced on a trampoline, Katie had less energy. Says an onlooker, "She looked pretty groggy."

Of Holmes' marriage to Cruise, an insider notes, "Their relationship isn't on shaky ground, but things definitely aren't perfect."