Justin Timberlake and Amanda Seyfriend sizzled at the Los Angeles premiere of their new film, In Time.

Held at the Regency Village Theater in Westwood, the premiere was also attended by the co-stars Olivia Wilde and Matthew Bomer, along with the film's director, Andrew Niccol (Gattaca, The Truman Show).

In Time is a new sci-fi picture that tells the story of how overpopulation is controlled by how much time is left in each person's life. Time is the most sought after currency, meaning the rich can live for as long as they can afford to.

This is physically the hardest job I've ever done, including world tours . . . I don't even dance. I don't know what I'd call it, Timberlake recently told Collider.

But still, I think it's the thing of, you know, you take a pro athlete: they warm up for an hour, they play a game for three hours, and then they go ice and they're done for a week. And they go next Sunday and they do the same thing. And we're on set for 10 hours, 12 hours and 10 of those some days we're running, he added.

Timberlake, 30, had a special guest with him at Thursday's premiere: his on-again girlfriend, Jessica Biel.

[They] became more and more affectionate, sneaking kisses, whispering to each other, and sharing quick back rubs and caresses . . . at one point, she pretended to punch him a couple times and he gamely bounced up and down like a jack in the box, a source told People.

In Time opens in theaters on Oct. 28. Scroll down for photos from the film's Los Angeles premiere.