From NY Daily News:

One explanation for Britain’s surging population is that cold weather makes them horny. It might also explain the very public hookup between Sienna Miller and English musician-slash-module Jamie Burke on a chilly Saturday night. The lanky Mr. Burke, who is currently modeling for Calvin Klein, counts Kate Moss and Lindsay Lohan among his previous paramours. He also attended a party for Miss Miller at the Gramercy Park Hotel after a Cinema Society screening of her latest film, “Factory Girl.”

And it was in the same hotel’s lobby that the two were spotted locking lips around 8 p.m. Saturday.

“There was no Fashion Week party or anything there at the time – they were just making out,” says a spy.

In addition to ex-fiance Jude Law, Miller has been linked to former co-stars including Daniel Craig and heterosexual actor Hayden Christensen. She and Burke have collected so many celebrity saliva samples between them you could probably clone half of Hollywood from their toothbrushes.