Credit: FameFlynet

She does own more than one bikini, you know. For her second day of rest and relaxation with loved ones in Mexico, Jennifer Aniston ditched a familiar-looking pink bikini to change into a strapless black bandeau bikini top (with sexy metallic clasp) and purple bikini bottoms. In new snaps from her vacation in Los Cabos, Mexico -- take Wednesday Aug. 21 -- the Horrible Bosses star, 44, looked relaxed and, of course, fit as she stood poolside in the sun. The organic food and yoga enthusiast "looked amazing" in her two-piece, an eyewitness tells Us Weekly.

While Aniston was seen covering up in a white towel, "her body looked ripped!" the witness marveled. The star is indulging in some well-deserved downtime after promoting We're the Millers, and is kicking back with fiance Justin Theroux plus pals Jason Bateman and his wife, Amanda Anka.

"Jennifer and Justin were sweet together and took a dip in the water to cool off," the source says of Aniston and Theroux, 42, engaged for a year. "They seemed really relaxed."

As Tuesday snapshots attested, Theroux's vacation physique is just as impressive as his wife-to-be's; going shirtless, the actor and screenwriter appeared more muscular and in shape than ever.

The sexy pair were spotted getting affectionate in the water, too. "She swam up to him and put her hand on his arm and started kissing him. They were very passionate."