Four lifelong teenage friends just entering womanhood buy a pair of thrift-store jeans that miraculously fits them all.

OK, so it may not be up there with the Turin Shroud when it comes to manifestations of the supernatural but the story needed a hook. And that's it.

Off on summer hols - their first time apart - they agree to share the iconic blue jeans by mailing them to each other each week...but "never wash out the magic."

Softly-spoken Lena (Bledel) heads off to the idyllic Greek island of Santorini where she causes a rift in her family by dating a hunky fisherman.

Leggy athlete Bridget (Lively) goes down Mexico way to soccer camp where she forces herself on a blonde beefcake sports instructor.

Volatile Carmen (Ferrera) - who it's difficult to believe would squeeze into jeans that are a snug fit for 6ft Bridget - hopes to spend some quality time with her divorced dad.

But when she arrives in Charleston she discover the spineless wimp hasn't told her about his new all-American family and his impending nuptials.

Poor old Tibby (Tamblyn), the rebel of the pack, is left back home stacking shelves at a local convenience store.

However, even she finds adventure when she hooks up with young leukaemia sufferer Bailey (Jenna Boyd) and they begin work on her pet project - a "suckumentary" about the banality of everyday life.

The syrupy premise of this yarn - based on the bestselling novel by Ann Brasheres - would have the more sceptical reaching for their coats.

However, it's worth sticking with it because the four lead performances are pretty impressive and there are moments of genuine tenderness.

Of course, that's tenderness in an American way - everything's sugared with indie ballads and more hugging than is strictly necessary.

But it's likely to score highly with a teenage audience moving on from The Princess Diaries to something more substantial.

Tim Evans