Olivia Culpo can't get enough of her superstar boyfriend Christian McCaffrey ... sharing a smokin' hot bikini photo with the NFL running back on Valentine's Day.
Culpo posted the shot of CMC holding her up in his arms on a vacation in paradise ... captioning the pic with a mushy love note.
"My best friend u2764ufe0fu2764ufe0fu2764ufe0f happy Valentine’s Day baby @christianmccaffrey," Olivia wrote on social media.
Of course, the two love birds are no strangers to PDA -- they show their love for each other quite often on trips and in their everyday relationship.