Katie Goes the Distance!

Following in the footsteps of Oprah Winfrey and Diddy, among other celebs, the Thank You For Smoking star tested her mettle by running the annual New York City Marathon on Sunday.

Holmes―otherwise known as racer F127 per the number that graced her purple tank top―donned a dark FDNY baseball cap and kept a low profile for much of the race as she and 40,000 other long-distance runners labored to complete the 26.2 mile challenge, considered the marathon of all marathons.

About 15 miles in, the tiring thespian got a boost from her superstar hubby who, while holding the couple's daughter, Suri, in his arms, met her on First Avenue in the Upper East Side and planted a quick kiss on her as she ran by.

Upon crossing the finish line in Central Park at approximately 3:30 p.m., an elated Holmes was greeted heartily by Cruise, his mother and her parents, who flew in from Ohio.

Holmes clocked in at five hours and 29 minutes, not bad for someone who reportedly trained for three months, but exactly an hour behind Oprah's mark.

According to People, TomKat and family members subsequently headed over to a private banquet Cruise threw for his missus by Tavern on the Green where the Top Gunner found himself in hot pursuit of their infant daughter who was racing around the tent.

"She's a runner!" he exclaimed.

Later on back at the twosome's hotel, Holmes, cradling Suri, admitted she was "good" but "feeling very tired."

When asked what the toughest part of the all-borough run was, she replied, "They were all challenging."

A rep for the actress declined to comment on the race.

News that Holmes was planning on tackling the marathon, one of the Big Apple's biggest sporting events, first surfaced in OK! magazine a few weeks ago.

Among the other notable names competing this year was cycling legend Lance Armstrong, though his latest, romantic interest, former Full House alum Ashley Olsen, was nowhere to be seen.