Olivia Ponton vs. Livvy Dunne -- Battle Of The 'Olivias'

Think fast 'cuz this sexy snap of Olivia Ponton and Livvy Dunne will blow your minds.

Both beach babes were caught sporting a striped bikini for a photoshoot -- this one is a tough call, but the question here is: Who'd You Rather?!

We're calling this the battle of the Olivias ... Livvy's government name is Olivia Page Dunne ... so that counts!!!