Sources close to Birdman tell TMZ ... the music mogul is firmly backing Jacquees' claim to the throne, and anyone disputing that notion needs to stop hating and bow down.

As you know ... Jacquees started a huge debate when he declared himself the best R&B artist of his era, a statement that's spawned tons of backlash and outrage.

People across the music industry started weighing in on the topic ... with Charlamagne Tha God emphatically telling us the crown still belongs to Chris Brown and Miguel.

Birdman, Jacquees' label head, had largely remained silent on the matter ... until now. We're told the Cash Money honcho loves the fact Jacquees made such a bold statement and feels it's about time his artist told the world what's really good.