"The O.C" star and soon-to-be mother Rachel Bilson rocked her sexy bikinis baring her baby bump with Hayden Christensen while on a vacation in Barbados.

Rachel Bilson, who is about five months pregnant, was clad in black, strapless scalloped Marysia bikini on Sunday, the Daily Mail reported. She was wearing black shades to protect her eyes from the sun's heat while she holds her mobile on her hand.

Walking barefooted in the white Caribbean sands, the 32-year-old actress also carried a boogie board as her boyfriend of seven years took photos of her in his orange boards shorts.

The couple was also seen in the past days snorkeling in the pristine waters and enjoying the company of some friends since they jetted to Barbados in May 22, a day after E! News confirmed that the actress is expecting a baby.

The pregnant Rachel Bilson was also seen wearing a two-piece mismatched halter-neck bikini. She paired her black bikini with an Aztec top that perfectly matched her raven hair. Meanwhile, actor Hayden Christensen looked hot in his floral printed shorts.

The pregnant Rachel Bilson gave a glimpse of her hot behind and growing baby bump as she walks with her long-time boyfriend by the beach.

In an interview with Health magazine's June issue, pregnant Rachel Bilson talked about her dream of creating a family with her beau.

"I've always wanted to be a mom. I have always wanted kids. I can just see this little toddler waddling around the house," the "O.C" star said.

She also shared how actor Hayden Christensen supports her pregnancy and that he is set to be a devoted father to their soon-to-be child.

The couple met in the set of "Jumper" in the 2007 where they started dating. They were engaged in December the year after and ended their relationship in August 2010. The two got back a few months later.