We’ve heard all about the fabulous time that the “Gossip Girl” cast had while shooting the Sept. 13 Season 4 premiere in Paris, but back on the Upper East Side, trouble was brewing. Nate (Chace Crawford) has spent his summer sinking to new lows courtesy of Chuck’s little black book, but when he meets Katie Cassidy, he’s inspired to clean up his act.

“This is definitely a big story for us,” says executive producer Stephanie Savage. “Katie’s with us for a good long time — at least for the first half of the season.”

Of course, the “Melrose Place” star isn’t what she seems. If there’s anything we’ve learned from “Gossip Girl” over the years, it’s that no newcomers arrive in town without some skeletons in their always-fashionable closets. Cassidy’s character Juliette is no exception to the rule.

“By the time the mystery is over, you’ll know everything there is to know about Juliette,” Savage teases. “Her entire back story will be revealed.”

After watching the first two episodes of the season, we thought that Cassidy would make an excellent Gossip Girl. She’s definitely got her eye on all of our Upper East Siders, and nothing slips by her. Not so fast, Savage tells us. “We’re not going to find out who Gossip Girl is this season,” she says definitively.

As for Juliette’s romance with Nate, Savage says, “The relationship definitely starts off as something with an agenda behind it, but by the end, it’s real for both of them.” She laughs. “Isn’t that always how it happens? You start a relationship trying to use somebody and you fall for them every time.”

We can’t wait to see Juliette tangle with Blair (Leighton Meester) and Serena (Blake Lively), but B and S may have their hands full at the moment as their stories unfold on the Columbia campus.

“It’s a really fun story that our audience will really like,” says Savage. “The center of our show is back in the right place, Uptown. It’s a collegiate, classically preppy environment that’s just perfect for our characters.”

Credit: blog.zap2it.com

Nate Archibald is about to find love on the next season of “Gossip Girl.” And he’s finding it with former “Melrose Place” star Katie Cassidy, who’ll join the show this season to bring a little spice to Nate’s love life. And according to Chace Crawford, who plays Nate, his new leading lady is a bit spicy offscreen too.

“Katie’s great! I know Katie, so she just got in [and] she just started like three weeks ago and I think 10 or 12 episodes she’s here for,” Crawford told MTV News on Wednesday at the New York City premiere of his gritty drama “Twelve.”

“She’s obviously a raging, conniving mean girl at the end of it. She sort of does her thing,” he added about Cassidy’s story line. “They can’t be straight-up but she’s fun, her character.”

Not only are fans excited to see Nate get some action this season, but they’re also looking forward to seeing what kind of international antics the “Gossip Girl” crew gets into during their trip to Paris. Unfortunately for Nate (and Crawford for that matter) he didn’t get to join in on the fun.

“I didn’t get to go to Paris! I don’t know [why]!” he said. “The girls are shoving each other around in fountains and [the rest of us] shoot in New York City, just all small- town New York City.”

So, was Crawford a little jealous that Ed Westwick’s Chuck Bass got to go to France? Well, he thinks Bass kind of deserved it after what he endured in the last season finale. “Of course he did! He got shot [on camera last season] and so he had a cane and the whole thing. Maybe they’ll send us to Costa Rica,” he said. “We’ll see!”

MTV News recently caught up with Leighton Meester, who gave us a few more details about Crawford and Cassidy’s onscreen romance, teasing that she might not be exactly who she seems.

“I think she’s coming on the show, maybe, to cause a little bit of trouble,” Meester said. “She might not say it, but I will. I think she’s very much capable of that, at least in the show. I think [Nate’s] a total playboy and needs to be single and I think [Katie’s character] is a bad girl, so maybe they are good for each other, actually.”