Pete Davidson and Ariana Grande. Picture: Instagram

Pete Davidson took to Instagram at midnight to wish his fiancee Ariana Grande a happy birthday and gush about how she is "the most precious angel on earth".

The 'No Tears Left to Cry' hitmaker enjoyed a meal out with friends, her brother Frankie and her husband-to-be last night to celebrate turning a quarter of a century, and the 'Saturday Night Live' star took to Instagram after to gush over Ariana.

Alongside a polaroid picture of him carrying the pop star on his back, which he posted just after midnight, Pete wrote: "Happy birthday to the most precious angel on earth! you're my favorite person that ever existed :) i love you sm [sic]"

He later added a second picture of the pair, captioning it: "one more for the queen. words can't express what a real f***ing treasure this one is [sic]"

Ariana took to Snapchat to share pictures of her various birthday cakes from the night, which each had black and white photos of her throughout the years printed onto the icing, including a main with one candle, which read, "Happy Birthday Ariana!", and a sweet one of her as a child with a rose in her hair.

The couple shocked the world when they announced their engagement after only a few weeks of dating, but the couple are head-over-heels in love with each other.

Pete, 24, recently admitted he feels like he's won a contest following his engagement to the 'Dangerous Woman' singer, who has previously dated the likes of Big Sean and The Wanted's Nathan Sykes.

During an appearance on the 'Tonight Show', host Jimmy Fallon joked: "Now, you know, that you didn't have to get engaged to Ariana Grande to come on our show."

But Pete replied: "I did though. I feel like I won a contest. I'm f**king lit, Jimmy. It's so lit."

Last week, the pair reportedly splashed out on a huge five-bedroom apartment in New York City.

The lovers were spotted furniture shopping in order to kit out the lavish abode, which is located in the upmarket Manhattan neighborhood of Chelsea.