TV star Patrick Dempsey, the star of "Grey's Anatomy", returns to the Le Mans 24 Hour Race this weekend, four years after his debut in motor racing's oldest active endurance race.

Best known for his role as neurosurgeon Dr. Derek Shepherd in the hit US medical drama, Dempsey will team up with experienced duo Joe Foster, his motor sports business partner, and Patrick Long to pilot the Dempsey Del Piero-Proton Porsche 911.

"It's great to be back, we are really thankful to be here, and I forgot how much fun it is to be at Le Mans," said Dempsey, 47, whose team was seventh fastest in the GTE-AM class during Thursday's qualifying sessions.

"Patrick Long is such a talented driver and Joe has worked so hard just to get us back here, he has really stepped it up, and is always there for us. Really, this is just a celebration of just being here," added the actor.

With heavy rain forecasted for the weekend, Dempsey, who was behind the wheel of a Ferrari during the 2009 edition, said his previous exposure to the feted Circuit de la Sarthe would prove invaluable.

"I could feel my experience from 2009, but it was a little challenging at first in the rain to relearn the track, but it was also really important to have that opportunity in the wet. The last time here I didn't really have any time on a wet track."

The trio of drivers will also be the only all-American entrant in this year's field, as the race celebrates its 90th anniversary, a fact not lost on Dempsey.

"We are the only all-American driving team and I think that means a lot to all of us. The history and heritage of that is so impressive and hopefully we can leave a mark and make a contribution in that great legacy," said Dempsey.