Michelle Williams and Spike Jonze were apparently feeling a mite frisky after watching the film that was responsible for bringing them together. People says they didn't try to hide their touchy-feeliness following a screening of their moniker-challenged movie "Synecdoche, New York" Wednesday night in Manhattan.

The wispy squeezes, who got to know each other while making the flick last year (she stars; he produced) and were first seen cozying up over the summer, remained in close contact after the film ended.

When they moseyed out of the theater, Spike rubbed Michelle's back and slipped his arm around her teeny waist.

The mag says Williams, 28, and Jonze, 38, were equally hands-on in the lobby as the actress chitchatted and shared popcorn with co-star Catherine Keener.

"He couldn't seem to keep his hands off her," says an onlooker. "It was very cute."

But cute apparently turned to amorous at the film's afterparty, where the pair remained so suctioned they were "practically spooning" as they mixed and mingled with the crowd, according to an eyewitness.

And things continued to heat up as the evening wound down.

Michelle recaffeinates while daughter Matilda tests out her Halloween costume in New York on Oct. 15. (©www.splashnews.com)

Michelle, who is mom to not-quite-3-year-old cutie-pie Matilda (she remains the spitting image of her late dad, Heath Ledger), supposedly enjoyed a "mini make-out session" with Spike as they headed to the elevator.

Meanwhile, in other, less palatable PDA chatter, Ryan Seacrest found time between his dozen or so hosting gigs to put the moves on a "mystery woman" while whooping it up in New York last week.

That's according to FoxNews.com, which says he was partying with fellow "American Idol" headliner Randy Jackson at a local hot spot when -- and we're quoting here, so don't blame us if your lunch repeats on you -- "ultimate ladies' man" Seacrest got to know a "hot lass" named Mariana.

"Sparks were flying as the two locked lips immediately, and would not stop making out the entire afternoon," says a seemingly eye-rubbing spy.

On the plus side, we may be spared any overt displays of septuagenarian lustiness from Jack Nicholson, who has decided he's reached an age where public enthusiasm for pretty young things "doesn't look right."

"It's not so nice when you are 71 and looking for some action," the London Guardian quotes him as saying. "I feel uncomfortable doing it in the limelight -- so from now on I'll do it when it's right."

But chances are the legendary lady-killer won't have too much trouble finding a member of the opposite sex to keep him company.

"Happily, when it comes to girls hitting on me," says Jack (while grinning, we're assuming), "I'm not undernourished."