Rachel Bilson Impresses In Skimpy Bikini With Poolside Cocktails

Rachel Bilson had fans rushing to hit "like" as she showed off her swimsuit body and cocktails for a poolside set of Instagram photos last month. Celebrating summer in her July 15 share, the 42-year-old actress stunned in a teeny bikini, posting to promote tequila brand 21 Seeds and with many fans thinking she just hasn't aged. All smiles in her girly gingham swimwear, Rachel posed from an outdoor bar decked out with the brand's drinks, also holding one as she stood by a swish pool and lawn. The O.C. star, who referenced the show she starred in with a mention of "old times," has actually reprised her Summer Roberts role just for the campaign.

Scroll for all the photos. Looking closer to 25 as she smiled for the camera, Rachel wowed in a low-cut bikini in pink and white. Flashing both her curves and her toned abs, the TV favorite flashed hints of her swimwear straps while sporting her dark locks down, looking glamorous, but also not OTT. Holding a glass of tequila with crushed ice and lime in it, Rachel placed a manicured hand on the nearby bar, one laid out with three bottles of 21 Seeds tequila.

Wearing hoop earrings and showing off a rosy glow from warming makeup, Rachel returned laughing and chatting away to a crowd in a swipe right before posing indoors and in a stylish green dress. In a caption, she wrote: "#ad Just like old times... but with way better cocktails  @21seeds #21seedsservingsummer 21SEEDS Infused Blanco Tequila. 35% Alc/Vol. Imported by Diageo, New York, NY. Please do not forward or share with anyone under 21. Please drink responsibly."

"Girl you don't age!" one fan replied. Agreeing, another wrote: "You look the same as you did first time I saw you on there."

The entire 21 Seeds campaign revolves around The O.C. and even has the show's executive producers on board. In its pre-campaign research, 21 Seeds found that 81% of consumers respond fondly to recalling old times, precisely why they asked Rachel Bilson to reprise the role she became famous for over 20 years ago.

“When 21 Seeds called to ask me to step back into my role as Summer, it was an easy yes, especially when I heard Josh Schwartz and Stephanie Savage were involved. I always say I would do anything with them at the drop of a dime,” the actress said in a statement.

Rachel Bilson is keeping Barbiecorealive. Just three days ago, the Hart of Dixie star wowed in a hot pink, floaty minidress with a flower waist detail and cut-outs. "Summer Barbie," she wrote, tagging luxury designer Valentino for her dress. She even wore hot pink heels and a purse to match.