James Franco's new movie "The Adderall Diaries" features the sultry actress Amber Heard, who stars as Lana Edmund. The 36-year old actor plays the role of Stephen Elliott, a writer that chronicled a notorious murder trial and got linked to a self-confessed murderer. The movie is based on the groundbreaking memoir of Stephen Elliot and is directed by Pamela Romanowsky.

We all know that James is a ladies' man so it must have been tough for him to keep his hands off on his lovely co-star. For those who are not aware, Amber is currently engaged to Johnny Depp. The "Pirates of the Caribbean" star showed his support for his girlfriend by visiting her on the set. Aside from that, he is always seen wearing Amber's engagement ring, because it was too big for her.

Last Friday, the 28-year old actress was caught giving Johnny a passionate kiss while on set for James Franco's new movie. He stopped by to see his Amber before leaving for Boston where he will shoot a film based on the life of infamous gangster James 'Whitey' Bulger.

Since Johnny is away, James finally had a chance to do a little flirting with the actress. The two were caught giggling while they pretend to ride a motorcycle together for their scene. Amber looked hot wearing a leather jacket paired with white skinny jeans.

She had her long hair down and was wearing a pair of black-rimmed eyeglasses just like what James was wearing. They actually looked great together and there is definitely chemistry between the two stars of "The Adderall Diaries".

Amber sat comfortably on the back part of the motorcycle and James was caught having his right hand on her leg. Too bad the paparazzi were able to catch that flirty move. I wonder how Johnny Depp feels about it. Since "The Lone Ranger" actor is a pretty cool guy, then I'm sure he isn't bothered about it.

Let's just hope that the on-screen romance in James Franco's new movie "The Adderall Diaries" won't come into real life.