Gwen Stefani Gavin Rossdale couple married husband wife yacht tank top white sunglasses necklace boat

Gwen Stefani bared her prefect bod as she frolicked around Cannes with the fam on a yacht -- but not just any yacht!

The Stefani-Rossdales got to travel in ultimate style (is there any other way?), because Russian billionaire Roman Abramovish let them borrow his rig ... aka the world’s largest expedition motor yacht.

Not a bad way to get around Cannes!