(Getty Images | Splash News)

Marc Jacobs's career revolves around making women feel beautiful with his lines of clothing and accessories, but the fashion designer has clearly been paying attention to his appearance too.

Celebrating his 50th birthday in Rio de Janeiro, Brazil, Jacobs, who is on vacation with his boyfriend, flaunted his toned body during an afternoon on the beach. It's a marked difference from a few years ago,when he sported a more casual look.

"I never took care of my appearance," he told Harper's Bazaar in 2010. "I was like, 'Who cares? I'm in the studio 16 hours a day and nobody sees me."

But after seeing a nutritionist and cutting out caffeine, sugar, white flour, and dairy, Jacobs dramatically improved his appearance, and, he says, his general health.

"I became so much more confident, so much more trusting," he said. ""Everything, it all sort of changed."