Jimmy Iovine -- I Book the Best DJs for Liberty's Birthday Bash (PHOTOS)

Jimmy Iovine threw a huge, Bev Hills birthday bash for freshly-iced fiancee Liberty Ross over the weekend and it's safe to say having his own music label made party planning a little easier.

Iovine, who co-founded Interscope, called his pals from Disclosure to headline the fete. They're one of the biggest DJ acts -- they're signed to Jimmy's company -- so it probably took one call to book them.

As for who hit the dance floor ... we're told the usual crowd showed up ... ya know, Oprah, Brian Grazer, Russell Simmons, Mary J. Blige, Lee Daniels and "Selma" director Ava DuVernay.

Catering featured the best of both worlds ... Nobu and Roscoe's Chicken and Waffles.

Ross turned 37 ... imagine her 40th.