Like it or not, Scarlett Johansson is most definitely involved with Oscar-winning actor Sean Penn - and here's the photographic proof!

The hot and heavy twosome dined out at Cecconi's in West Hollywood on Saturday night and, in the car on the drive home, ScarJo decided to keep her head down and "hide" on Penn's lap.

A source inside the restaurant tells X17online:

    "They were definitely on a date - these two are way more than just friends. Sean is known to be a tough guy but Scarlett seems to soften him. He's a boy in love when he's around her - or at least a boy in lust."

Both stars have been dating since January of this year, with reports claiming the actors started "hooking-up" after Johansson began filming We Bought a Zoo with Matt Damon in Los Angeles.

ScarJo, 26, split from hubby Ryan Reynolds in December 2010. Sean Penn, 50, finalized his divorce with Robin Wright in August 2010.

What has Johansson said about monogamy in the past? Click below the jump to find out!