Oops, Britney Spears did it again! The pop wreck has come under fire after being photographed her smoking in front of her two-year old son.

Having agreed on custodial arrangements with her ex-husband Kevin Federline last week, Brit Brit was snapped exposing her eldest son Sean Preston to second-hand smoke while he tried to grab her cancer sticks.

The Toxic singer is seen in the photos standing in a bikini next to Sean Preston as she lights up. The curious toddler holds a lighter in one hand and reaches for a pack of his mother's Marlboros with the other.

Taken from the star's Beverly Hills, California home, Spears is snapped reaching down for the pack to stop her curious son taking them.

Studies have proven links between second-hand smoke and childhood illnesses, including ear infections, bronchitis, asthma and other respiratory ailments.