Spoiler Alert! Jessica Simpson Shows Up to Judge Project Runway Finale

Pop star says it's an honor to chosen to help select winner of reality show at Fashion Week showcase

Uh-oh, we could be waiting awhile before we have a verdict on the winner of this season's  Project Runway.

Jessica Simpson was in the house today to serve as the guest judge on the finale of the reality show as it showcased its top designers during Mercedes-Benz Fashion Week at Lincoln Center. She was psyched for what she called the "big bang," wowing the crowd in a dazzling charcoal Michael Kors mini-dress.

Just don't ask which of the contestants was her favorite...

"I'm going to be torn on who I want because there's a couple that I really like, so we shall see," she tells E! News. "It's exciting."

But the singer and part-time designer, who debuted a denim line of her own this week, says she's keeping her favorite "top secret."

Simpson sat with regular judges Kors and Nina Garcia, while 10 designers from the show presented their collections.

But the usually sweet Simpson says she'll try her best to judge honestly and that fans and designers may be shocked by what she has to say.

"I'm a nice Southern girl so it will be hard for me to make somebody cry, but you never know whats going to come out of my mouth though. I'm used to being criticized so now I get to do it!"

As for her own debut, she says that all the important people in her life were there supporting her, including new boyfriend Eric Johnson, who thinks the jeans look "sexy" on her. 

Today's runway show was a hit, even though several of the designers already knew they'd been cut. Because the finale takes place now but the current season is only six episodes old, producers need to make sure there are no spoilers leaking out.

Host Heidi Klum, who opened the show wearing a bright red pantsuit, said she already knows the three finalists—but there is one she prefers.

"Today we are going to have to show ten, but we have our three that we already," she tells E! News "I do have a favorite. I play devils advocate sometimes with the other judges and on TV."

Heidi also complimented her guest judge's shoe line, saying Simpson's sales are "through the roof."

"I'm looking forward to working with her," she says. "She's been watching all the episodes with fresh eyes so we shall see what she thinks."