We think it's adorable how obsessed with her he is!

Pete Davidson just took to Instagram to gush about fiancee Ariana Grande in honor of her 25th birthday today, and it's obvious that the SNL funny man is head over heels for his lady love.

"Happy birthday to the most precious angel on earth! you’re my favorite person that ever existed 🙂 i love you sm,” he captioned a photo of the pair. He wasn't done, though!

"One more for the queen. Words can’t express what a real f*cking treasure this one is," he wrote on another.

They've had a real whirlwind romance to say the least! They began dating in May and got engaged after less than a month, and recently moved in together in NYC. Before that, they both were in long term relationships, he with Larry David's daughter Cazzie and she with rapper Mac Miller.

We guess when you know, you know!