Model Mara Teigen's $50k Bday Bash

Model Mara Teigen's new mystery boyfriend footed the $50,000 bill for her 22nd birthday, and the luxurious event had everything you'd want at an all-chick celebration ... except pillows.

Mara's party went down Sunday at the Beverly Hills Hotel in the Presidential Bungalow suite, which goes for about $27k a night. Dude also threw in a 6 ft tall orchid arrangement for $3,500 and a $2,500 cake. Not to mention the $12,000 diamond Cartier bracelet she got as a gift.

We're told she's been with the BF for about 8 months, but wants to keep his identity under wraps. And if he's gonna keep dropping this kinda coin, we say ... no need to rock the boat.

As for the guest list ... Justin Bieber's recent fling, Sahara Ray, "DASH Dolls" star Durrani and Carl's Jr. model Emily Sears were all there in white swimwear.

Still ... no pillow fight. Bummer.