The 47-year-old actress looked unrecognisable in a strawberry-blonde hair pulled into a ponytail, reported People magazine.
This is the first time the 'Pretty Woman' star has lightened up her locks this much for a non-work-related reason, reported the magazine.
Last time Roberts was seen sporting golden locks was in the ads for Lancome.
The star was lying low in the weeks following the death of her half sister Nancy Motes but she resurfaced in LA with golden locks.