Jessica Alba has made a graceful post-pregnancy return to acting as she films her upcoming movie An Invisible Sign Of My Own.

The Sin City star was back in costume and looking her best in her new role, on set in New York.

The new mum will be playing a mathematical genius who gets a serious illness which causes her to lose the will to live.

But Jess' character learns to cope with her circumstances by teaching maths to children.

See Jess in action below