“Gossip Girl’s” Ed Westwick’s hard-partying lifestyle is starting to catch up with him. Not in the traditional Hollywood sense of shipping himself off to rehab (yet), but in an equally detrimental way – at least for an actor. Ed is a fan of the drink – but not of moderation. As a result, he’s put on some chunk, and people are starting to notice. And talk. In fact, the costume department at “Gossip Girl” is getting downright annoyed with having to purchase a new wardrobe to compensate for the new junk in Ed’s trunk.

At the Gossip Girl wrap party at New York’s Bowery Hotel, Ed Westwick turned heads — but for all the wrong reasons.

“He looked totally unkempt, like he hadn’t showered in days,” says a guest at the March 28 event. “All he did the entire time was play beer pong with Heineken. He was drinking a lot.”

That’s nothing new for Ed, who has treated New York like his personal playground ever since being cast as Chuck Bass on Gossip Girl in 2007. But in the hit show’s second season, Ed, 21, has put on an estimated 10 pounds, and his partying is starting to hurt his appearance.

“Ed has been gaining a lot of weight — not just around the waist, but throughout his whole body,” says an on-set source. “First, the costume department had to buy him new, bigger pants. Then, his shirts and jackets got way too snug. The costumers even requested that producers talk to Ed — they don’t want Chuck to be fat!”

Ed has gotten flack from his castmates, too. “They filmed an episode with a pool scene,” another set insider reveals. “Ed was completely not in shape, and people were making fun of him.”

[From In Touch received via e-mail]

I have to wonder if Ed’s castmates were making fun of him to his face. That’d be pretty mean spirited. On the one hand I feel badly for him – gaining weight is always embarrassing. On the other hand, if this were a female celebrity, every single tabloid would be up in arms and pasting unflattering pictures all over their covers. In Ed’s case, it’s a short little blurb in one of the less-successful weeklies. Worse things have happened.

This is only how it works for me, but I find it a hell of a lot easier to lay off the booze than the cheeseburgers. Nixing alcohol is always my first course of action. Ed might want to try toning it down on one or the other. Because guy or not, in another 30 lbs he’ll be on the cover of Us Weekly.

Here’s Ed on the set of ‘Gossip Girl’ filming on location in Manhattan last Tuesday. He may have put on some weight but he looks like he’s still completely height-weight-proportionate. Images thanks to WENN.com .