She is famous for her voluptuous figure, often outshining the 'size zeroes' on the red carpet with her killer curves.

But Scarlett Johansson was spotted in Malibu over the weekend looking more curvaceous than usual.Which is perhaps why the actress was out pounding the pavement, working up a sweat with a jog alongside her new boyfriend Sean Penn.

Scarlett's rounder stomach was noticeable under her tight exercise gear, a small bump protruding beneath her grey vest and black lycra leggings.

The 26-year-old went incognito in a cap and sunglasses, keeping her head down as she concentrated on her workout.They have been snapped together a couple of times, including last weekend at Reese Witherspoon's wedding.

But Scarlett's representative has denied any romance saying the pair have been 'friends for years' - despite recent pictures of the pair at lunch where Scarlett placed her feet in Penn's lap.