Mariah Carey to Fergie: Don't Listen to the Haters!

It ain't ALL hate for Fergie after that bizarre national anthem at the NBA All-Star Game -- with Mariah Carey dishing out some advice on how to deal with the negativity.

A glammed up Mariah was leaving Sweet Chick on Fairfax Sunday evening -- when she gave Fergie one very simple tip.

By the way, Mariah has some experience in this department ... the haters came out in force for her New Year's Eve performance a while back -- but it didn't seem to faze her.

Aside from Mariah, Takeoff from Migos and NBA star Karl-Anthony Towns also had Fergie's back.

Not everyone has been so supportive ... "Saturday Night Live" star Leslie Jones hated it -- and judging by Draymond Green's face, he wasn't a fan either.

Still haven't heard from Fergie yet -- but we'd LOVE to hear her thoughts on it.

Stay tuned ...