Blackpink's Lisa could melt "Ice Cream" with her latest hot look ... an itty-bitty string bikini by Louis Vuitton.

Check it out ... the Thai performer, who is a longtime member of the K-Pop girl group, dons a teeny tiny red-and-white bikini covered in Louis Vuitton's signature monogram in a series of new photos posted to Instagram.

Her bathing suit selection is perfect for her lavish tropical getaway, and it's also on brand ... she's famously an ambassador for the iconic French fashion house.

And, after taking a closer look at Lisa's sizzlin' vacation pics, you can understand why Louis Vuitton tapped the starlet to rep their brand in the first place.

The "How You Like That" artist looks beyond jaw-dropping in the minuscule 2-piece thanks to her fit physique ... which we're sure is courtesy of her many hours performing with her Blackpink bandmates Jisoo, Jennie, and Rosé.

While it's currently unclear where Lisa is soakin' up the sun, it is transparent that she's having the time of her life ... just look at her glow!!!

Lisa isn't the only one showin' off her bikini strings, however ... check out our gallery and guess the celebs beneath these lil' tiny straps!