SANTA MONICA, California -- One is a fast-rising TV star, nervously making the transition to feature films. Another is a sometime pop singer, hoping to establish herself as an adult leading lady. Then there's the third actor -- an Oscar-winning living legend looking to prove he's still got it.

With "License to Wed" having hit theaters Tuesday (July 3), we'll now be able to decide if it's any good, but this much we already knew: It's one of the more intriguing studio films to pop up in the hotly contested Hollywood summer of 2007.

"I think the funniest thing about weddings is the tension that is palpable in the air," John Krasinski said recently, talking about the little-comedy-that-could starring himself, Mandy Moore and Robin Williams. "As the day goes on, everybody sort of lightens up -- and that could be the alcohol. But the preparation for a wedding, when people lose sight of what the day's all about, get so stressed out and emotional? I think that leaves room for some pretty good comedy."

In the eyes of 23-year-old Moore, "License" is a refreshing alternative to Transformers, pirates and superheroes -- and, more personally, it's a chance to get past teen flicks like "Chasing Liberty" and "Saved!" while presenting herself as a credible, comedic blushing bride. "What's funny is all the crazy trials and tribulations and tests that our characters are put through as a couple in order to be certified to get married," said Moore, whose Sadie goes through a marriage-preparation class with fiance Ben that includes robot babies, blindfolded driving and absolute abstinence. "It all sounds pretty insane. Robin Williams' character really puts us through the ringer."

"John is very physical; he always wants to touch me," grinned Robin Williams, insisting that he learned just as much from his two young co-stars as they did from him. "Mandy, she has a whole psychic thing, where she does this [eye-rolling] and communicates her lines psychically. ... They are two sexy people and fun and really funny. There's a sweetness and a kindness about them that makes life really lovely, and for me, that was nice too -- because that was before I went to rehab."

As you can see, each of these three stars are launching "Wed" with something to prove. But as far as nerves are concerned, Williams' rehabilitation and Moore's post-"American Dreamz" reinvention would seem to pale in comparison to Krasinski's first starring role.

"To be honest, this is my first big movie, so I was terrified every day," the lanky, 27-year-old actor said.

To make the transition easier, Krasinksi said, he surrounded himself with as many people from "The Office" as he could find. "To come in and see familiar faces really made it nice; I felt like I was at home," he said of the cast, which includes Mindy "Kelly" Kaling, Angela "Angela" Kinsey, Brian "Brian" Baumgartner and director Ken Kwapis. "Ken being at the helm, who directs a lot of our episodes, was fun. He found a similarity of how he directs the show and tried to use some of the subtlety and the specifics of what it means to be in a relationship. Then, as far as having all those guys on set ... it was a blast."

"I'm a big fan of 'The Office,' " Moore said of the increasingly popular NBC show. "With Ken being a producer of the show, and having directed a bunch of the episodes, and John's involvement in this movie as well, it totally sold me. ... But then we kept getting all these fun cameos from Angela and Mindy and Brian -- and being a big fan of the show, I was like, 'Cool, what "Office" castmember is coming by today, guys?' "

If enough "Office" fans get up off the couch and make their way to the movie theaters, who knows? Maybe "License to Wed" could become a sleeper hit for those who'd rather watch Williams playing the fast-talking Reverend Frank than Shia LaBeouf running away from a green screen. And if that's the case, maybe real-life wedding-prep classes will similarly take off.

"I [agree with] anything that gives you a running start, some tools," reasoned Robin Williams. "The passion? The sex? That's your call. There are manuals for that, different courses -- some of them are hands-on, and some of them are videotapes."

Flashing a grin, the veteran comedian began making boom-chicka-wow-wow guitar noises. "You know, the bad porn ... I am the plumber," he laughed. "Courses that would help you, that would be cool. ... Anything that gives you any knowledge of your partner is helpful."

Knowledge of your partner is also important to Mandy Moore -- who realized during filming that the more she learned about Krasinski's opinionated and quirky character, the more she unearthed details about the real-life lucky stiff who'll eventually capture her heart.

"It's important to be with someone for me -- personally at least -- that is opinionated. But I also like someone that's a bit more low-key and mellow at the same time," the actress revealed. "John's character, Ben, is so charming and agreeable and sweet and funny -- and those are all characteristics that I would look for in a potential guy."

Judging by the way she's talking these days, if wedding-preparation classes do soar with "License," Mandy might want to go ahead and reserve herself a desk.

Check out everything we've got on "License to Wed."

Visit [article id="1488131"]Movies on MTV.com[/article] for more from Hollywood, including news, reviews, interviews and more.

For breaking news, celebrity columns, humor and more -- updated around the clock -- visit MTVMoviesBlog.com.

Want trailers? Visit the Trailer Park for the newest, scariest and funniest coming attractions anywhere.