Derek Shook/Splash News Online
05/21/2012 at 11:30 AM EDT
is known for many things: her acting career, her clothing line with twin sister Mary-Kate
, her boho fashion sense
. Not on the list? Showing some skin – or smiling.
But there's nothing like a Hawaiian vacation to turn that around.
Normally reserved in both her fashion sense and her facial expressions, Olsen, 25, let loose while on holiday, grinning in the surf in a printed bikini top and black bottoms.
The actress and fashion designer (and one of Vogue
's best dressed
) was photographed taking a dip in the Pacific and even smiling broadly for photographers last week.