DANA WHITE celebrates his 50th Birthday with MASSIVE party including Gwen Stefani & Don Henley

Dana White turned 50 on Sunday ... and his surprise birthday bash was INCREDIBLE -- with an amazing performance from Gwen Stefani and Don Henley busting out "Hotel California"!

The UFC boss had no idea the party was being set up at the Aria Hotel & Casino on Sunday night ... but when he arrived, the guy nearly lost his mind!!

White is a huge music fan -- his office is filled with memorabilia -- so to have the stars from "No Doubt" and The Eagles in the house meant a lot to him. Gwen performed several hits including "The Sweet Escape.