The divorce between pop star Christina Milian and "The-Dream" has turned nasty -- all because of Justin Bieber.

RadarOnline.com has exclusively learned music producer Terius "The-Dream" Nash wants to back out of an agreed deal with his soon-to-be ex-wife that would have given her 10 percent of his earnings on Bieber's hit 'Baby' -- which he co-wrote.

COURT DOCUMENTS: Read Christina Milian's Motion To Enforce Settlement Agreement

Now Milian has gone to a Georgia court attempting to have a judge enforce a settlement agreement the pair struck in October, last year.