Tim Gunn recently filmed his cameo for Gossip Girl, and let's just say that during his brief time on the New York set, he was not a big fan of Taylor Momsen.

It wasn't even her style that was the problem, either. It was her phone.

If the actress paid more attention to her lines instead of that, Taylor would be a lot better at her day job, Gunn says, calling Taylor both "sad" and pathetic."

"What a diva!" he says of the trouble-causing 17-year-old Gossip Girl star. "She was pathetic, she couldn't remember her lines, and she didn't even have that many. I thought to myself 'why are we all being held hostage by this brat?"

The main issue, the Project Runway star says, was her BlackBerry.

If he were a regular on the show, "I'd say, 'You know young lady, there are hundreds of thousands of girls who are just as attractive and even smarter than you. Why are you acting like this show is a huge burden on you?'" Gunn says.

"[Taylor Momsen] was on her phone during every single break. I wanted to tell her, 'If you weren't on your BlackBerry, you can actually retain this stuff.'''

Gunn says he's not trying to slander her, but "I'd just ask her 'do you want to share with me why you are always on your phone?' At one point the director leaned in and whispered to me, 'this is day in, day out, my life.' She annoyed the entire crew."

Harsh stuff ... yet not entirely shocking to hear, unfortunately. Sigh.

To show he's not a total curmudgeon, the fashionable fellow had kind words for Penn Badgley, calling him a "delight" to work with, along with the rest of the cast.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.