Credit: David Becker/

Back to the drawing board.

David Arquette and Entertainment Tonight reporter Christina McLarty have split after about five months of dating, he announced via Twitter late Tuesday.

"Sadly I'm single again," the actor and Dancing with the Stars alum, 40, wrote. "A long distance relationship proved to be too difficult."

After meeting on a boat party over summer 2011, Arquette and McLarty (the former domestic partner of Girls Gone Wild's Joe Francis) stepped out as a couple in late September of last year.

"She's adorable," he told Howard Stern at the time. "I'm not one to run around with different girls. I like someone that makes me feel good and that I can make feel good."

Adds a source of the breakup: "They are both OK with it. It's mutual. They knew it was going to be a problem when Christina got tranferred to NYC right after they started dating. They tried the bicoastal thing but it was too hard. . .. It was hard to break up but it just couldn't work like this."

Since separating in fall 2010, Arquette and estranged wife Courteney Cox (they share daughter Coco, 7) have remained amicable, and have yet to file for divorce.