Kate Winslet Shows Off Her Newly Toned Body -- And Her Hot Model Boyfriend

Kate Winslet and her hunky new model boyfriend, Louis Dowler, appeared majorly smitten Monday night at the San Sebastian Film Festival in the Spanish city of the same name.

Wearing a flattering one-shouldered little black dress that showed of her newly-slender, yet still fabulously curvaceous body and taupe, peep toed Louboutins, Winslet seemed hard-pressed to keep her hands to herself!

And, really, who could blame her. Dowler, who's appeared in numerous fashion campaigns (including this one for Burberry), is certainly easy on the eyes. The pair, who're both Brits, met at a party over the summer and, according to all reports, have been virtually inseparable ever since.

The Oscar winning Winslet and director Sam Mendes, her husband of seven years, have been separated for six months and live in New York City where their son, Joe (6) and her daughter, Mai (9), from a previous marriage, attend private school.

Things between Mendes and Winslet reportedly grew strained after he directed her in the heart-wrenching drama "Revolutionary Road," which saw Winslet reunite with her "Titanic" co-star, Leonardo DiCaprio. The film centered on a couple that fights a lot and ultimately breaks up.

Winslet had been working close to home, filming HBO's upcoming adaptation of "Mildred Pierce" in New York but will be heading to Chicago soon to meet up with Gwyneth Paltrow, Jude Law and Matt Damon on the set of their upcoming movie, "Contagion."

"They have discussed the idea of Louis going with her while she films so they won’t have to endure a long-distance relationship at such an early stage in what seems to be something pretty serious," a source told Britain's Daily Mail. "Kate hasn't been this happy in years."