LOS ANGELES, California (CNN) -- Actress Patricia Clarkson has a giggle whenever she thinks about the handwritten letter she received from the great Woody Allen.
Woody Allen, Patricia Clarkson, Evan Rachel Wood and Larry David worked together on "Whatever Works."
The actress, who first worked with the famed director on the 2008 film "Vicky Cristina Barcelona," was tickled by a letter on Allen's personal stationery in which he said he had written a part for her, "but if you have something better to do, I'll understand."
"You know, he had me at the letter," Clarkson said. "It's Woody Allen! 'If you have something better to do'? Woody, come on!"
Clarkson definitely made time to perform in Allen's latest film, "Whatever Works." The movie centers on a quirky, grouchy New Yorker -- played by the aptly cast Larry David -- who abandons his privileged life to become more Bohemian and hooks up with a younger woman played by Evan Rachel Wood.
David, the "Seinfeld" co-creator known for his curmudgeonly ways and his hit HBO series "Curb Your Enthusiasm," had appeared briefly in two earlier Allen films, "Radio Days" and "New York Stories." EW ranks every single Allen film
David said he was slightly hesitant about embracing a role as large as that of Boris Yellnikoff in "Whatever Works."
"I read the script and I looked at the first page and there's Boris all over the first page, then I turned to page 50, and there's Boris on page 50, then I went to the last page, and there's a big monologue by this character Boris, and I thought, 'Oh, wow, this is something,' " David said. "So I called [Allen] up on the phone, and I said, 'I don't know if I can do this, you're making a big mistake!' " Watch David talk about Allen encouraging him to "stretch" »
David said Allen convinced him that he could pull it off. He said he enjoyed his time acting for the iconic director who, he said, was great to work with and allowed his actors freedom.
"If you're not comfortable with something, he doesn't want you to do it," David said. "He doesn't mind if you change his words -- he's very easy. It was very easy to work with him."
It wasn't as easy to work with Clarkson, David said, because she is such an amazing talent.
"You forget that you're in the movie because you're just enjoying what she's doing," David said. "Then all of a sudden it dawns on you, 'Oh, hey, I've got a line coming up, I better get back to this movie.' "
Clarkson, who recently garnered buzz for her appearance in the Justin Timberlake-Andy Samberg "Motherlover" SNL skit, plays Marietta, the mother of Yellnikoff's young paramour.
She echoed David's admiration and said working with the comedian in an Allen-helmed film was incredible.
"You have a part written by Woody, you're being directed by Woody, and then you're acting with Larry David," she said. "It's just genius, genius, genius, and then you have Evan Rachel Wood, who's this beautiful, amazing emerging star. I was in heaven every single day on that set."
The movie marks Wood's debut in a comedy, and like David, she found the experience a bit daunting at first.
"Not only am I doing Woody Allen dialogue, but opposite Larry," she said. "Thank God he was just as nervous as I was, because he does 'Curb,' but that's mainly improv, so he never had to really memorize lines before."
Her character Melody, Wood said, isn't exactly dumb, but she is earnest.
"She is incredibly naïve and just a very sweet Southern girl who sees the good in everything and everybody and is determined to have a happy life, while Boris is determined to have a miserable one," she said. "I think that's why they end up together. Opposites attract."
And even though Wood grew up in North Carolina, she said Allen encouraged her to tap even further into her roots for the role.
"Woody always told me, 'More Southern, more Southern,' " she said. "I was so worried about going over the top, and he really pushed me. I'm glad he did."
Although some of the characters hail from below the Mason-Dixon line, "Whatever Works" was shot in the mainstay setting of most of Allen's films, New York City.
Clarkson, who was born in New Orleans but lives in New York, said she marvels at how the director is able to attack similar themes like love, romance and the life of New York intellectuals while still keeping his films fresh.
"And yet, I don't know how he does it," Clarkson said. "And for me, this character, he takes this kind of archetypal Southern character, and he's such a Yankee, yet he figures out this beautiful way to come at this character fresh, which is almost impossible, and he did it."