Christina Kirkman's Sexy Trippin' with Tarte Pics

Christina Kirkman is on the viral Tarte Cosmetics brand trip to Turks and Caicos ... and she looks like she has the best abs on the island.

Check out these photos the former Nickelodeon child star uploaded on the 'Gram ... it's hard to look past her rock hard abs.

Christina is showing off her toned stomach in a sexy bikini top and some matching bottoms ... she's blinged out and wearing high heels too, with legs for days.

She also posted a fun bathroom mirror selfie ... she's rocking the same outfit, and multitasking while sipping a drink and holding a purse and her phone.