Justin Timberlake, Jessica Biel to star in movie together

Justin Timberlake and his actress girlfriend Jessica Biel are planning to combine their skills and produce a movie together, according to reports.

The couple - who  have been dating since May, are keen to start work on a new project, insiders claim.

"They've been together a while now and can't get enough of each other," a source reveals. "So the joint project seemed obvious thing to do."

But despite their blossoming romance, 25-year-old Jessica is already having doubts about acting with her popstar beau.

"Justin is very keen to do a comedy," the source tells Britain's Daily Record newspaper. "While Jessica wants to do something grittier because she's concerned about her image."

Since putting his music career in hiatus in 2004, the 'Rock Your Body' star, 26, has since stared in a variety of different movies including Alpha Dog, Southland Tales and as the voice of young King Arthur in last year's Shrek The Third.