Justin Timberlake and Jessica Biel 'kiss at premiere party'

Justin Timberlake and Jessica Biel made their rekindled romance official on Thursday (20Oct11) by attending a party for the actor's latest premiere together.

The on/off couple parted ways back in March (11), but they sparked rumours of a reconciliation after they began spending time together again in August (11).

The Hollywood pair has not yet confirmed the status of their relationship, but the stars made a statement by stepping out at a party following the Los Angeles premiere of Timberlake's new thriller In Time.

Timberlake and Biel were seen kissing at the bash, and they even stayed behind past midnight after most guests had gone home.

An onlooker tells People.com, "(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."