Naomi Watts, one of the stars of “Two Mothers,” acknowledged that she had the same visceral reaction to the film's love story as many in the audience.

“I was shocked on the first reading of the script,” Watts said at a question-and-answer session following the films first screening Saturday at the Sundance Film Festival.

The plot, in short, of what is one of the more controversial (and perhaps will be the most successful) films at this year's festival is, briefly: Two life-long best friends, Lil (Watts) and Roz (Robin Wright) have love affairs with each other's 20-year-old sons. The film was one cited by a conservative Utah group that asked the state of Utah to cut funding to the festival because its movies have questionable family values.

At one point in the Q and A, Watts explained the challenge of presenting the material — which at its core a tale of the friendship between two women— in a way that shifts the audience's reaction from judgement to forgiveness: “I've had relationships like that,” before catching herself, “Well, not completely like that. ” Still flustered, Watts added, “You know what I mean.”

Considering the close friendship of Roz and Lil, the relationships are practically oedipal and Watts refers to the dual affairs as the “unspeakable thing.”

“It's a secret that binds them. It's a drug they can't give up,” she said.

Director Anne Fontaine made the story into a beautiful movie, which might rob the flim of its power. It's too lovely. The two most beautiful moms in Australia have the continent's two hunkiest surfer sons and live in two beautiful homes overlooking a breathtaking bay—complete with dolphins— (for fun, let's just call it Blue Lagoon). Did I mention that Roz runs an art gallery and Lil works for a yacht designer?

But it's not as if we haven't seen plenty of movies about love between older men and young girls, passed off as adorable or at least acceptable. Even seeing Fred Astaire and Audrey Hepburn matched up in “Funny Face” is a bit uncomfortable.

“Two Mothers” could be easily parodied as “MILFs Down Under” or “Cougars in Paradise” or “Mommys' Mid-life Fantasy.” But the basic story, from a novella by Doris Lessing, explores the travails of inconvenient love that, as Watts explained, fills the voids of loneliness and fear felt by two women about to see their sons move on to adulthood.

Fontaine may have answered the family values critics about as well as she could, when she explained: “It's a very strange love story. But it is a love story. Not a sex story.”