Spencer Pratt, whose sister Stephanie was arrested for DUI over the weekend, broke his surprisingly long silence on the subject by sort of defending her.

Vaguely. He says it's easy to get caught up in a wild Hollywood lifestyle.

"I mean, I've had problems with drinking in Hollywood, but who doesn't?" a somber Spencer Pratt told MTV in reference to Stephanie and/or Holly Montag.

He says when you're having fun and living a wild and crazy life, it's hard to realize that there's anything wrong. It also doesn't help when club promoters and bar-goers are "giving you unlimited high-end alcohol," he says.

Speidi waves to supporters. All 12. [Photo: PacificCoastNewsOnline.com]

"If you're out at a club every night having drinks, you're drinking every night of the week," he says. "First, it starts off, 'Oh, I just love this dancing and having fun with friends.' But, even if you're just having a couple, [it adds up]."

Ironically, it was sister-in-law Holly Montag, not Stephanie, whose drinking is scrutinized on the current season of The Hills, including last night's show.

He reveals that on The Hills, he and Heidi had to "step in." Says Spencer Pratt, "Tune in, you'll see it click, when we're like, 'Yo, it's time to help Holly.'"

No word on whether he's also helping Stephanie ... with bail.