Toned and trim! Julianne Hough wows in a pink bikini on the Caribbean island

It isn't hard to see what Ryan Seacrest sees in girlfriend Julianne Hough given how good she looks in a bikini.

The 23-year-old actress flaunted her toned and trim beach body in a hot pink two-piece bathing suit while on vacation in St. Barts on Tuesday.

She wasn't shy about showing off her flat, muscular stomach as she towelled off after splashing around in the ocean with a few female friends.

Rockin' body of any age: Julianne Hough wows in a bikini while on vacation in St. Barts Tuesday

Her boyfriend, producer/host/entertainment guru Ryan Seacrest, joined his girlfriend of eight months on the Caribbean island.

He put a proprietary arm around his younger lady love as the two strolled down the beach after her fun in the sun.

The two looked relaxed in their low-key beach gear as they meandered down the stretch of sand.

The former Dancing With the Stars hoofer left her blue chambray shirt open to show off her bikini top and threw on some high-waisted pink shorts as well.

 

 

If you've got it, flaunt it: The 23-year-old wows in a pink bikini

The 37-year-old American Idol host went for a preppy look with long shorts, a white polo shirt and black cap; he held a pair of tasseled loafers.

On their romantic stroll, they ran into another high-profile couple: stylist to the stars Rachel Zoe and investment banker husband Rodger Berman.

The latter duo had their adorable nine-month-old son Skyler in tow.

Getting her tan on: The blonde bombshell laid out on the beaches of St. Barts earlier this week

The foursome chatted amiably before heading to a nearby house, where they toasted one another with champagne.

Julianne surely must have been celebrating her recent good luck: in addition to scoring one of the most hard-working men in Hollywood, her film career is also taking off.

She starred in the critically acclaimed Footloose remake this year, and has won the lead in the upcoming rock musical movie Rock of Ages.

 

Happy go lucky: We'd be happy if we looked this good in a bathing suit, too

Gal pal time: Hough hung out on the beach with her girlfriends before her boyfriend picked her up

The young bombshell plays Sherrie Christian, an ingenue who falls in love with an aspiring rocker in 1987.

Monster ballad hits of the eighties will be featured in the film, which is scheduled for a June 12, 2012 release.

Tom Cruise, Mary J. Blige, Catherine Zeta Jones and Alec Baldwin also star.