In a tented V.I.P. area, disaffected mommies, sipping Chardonnay as their sticky-faced toddlers twirled enthusiastically to the beat, perked up considerably at the somewhat tardy arrival of Cobble Hill celebrity Michelle Williams (Dawson’s Creek, Brokeback Mountain). According to a frighteningly observant mommy source, Ms. Williams was looking very late-60’s Mia Farrow with her blond pixie haircut, wearing a striped lavender-and-black baby doll knit jumper and dark Ray-Ban sunglasses, and pushing a pink Maclaren stroller that contained her 21-month-old daughter, Matilda (clad in a simple red cotton dress, diaper and purple Crocs). “She took her out and bounced her up and down near the front of the stage,” said the source, who also—quel scandale!—overheard a concert organizer gripe that Ms. Williams “was down for plus-one, and when she showed up it was suddenly plus-10.”

But curiously, there was no entourage in evidence; certainly not the actress’ fiancé, actor Heath Ledger; her only adult companion was a blond, slightly stockier woman (“looked more like a friend than a nanny” said the source).

“Unfortunately, Michelle is not available,” Ms. Williams’ publicist e-mailed The Transom when asked for an explanation.