Brian McKnight Sues Ex-Wife and Son Over Allegations About His Late Son

Brian McKnight says his ex-wife, one of his sons, some bloggers, and a newspaper rolled out a coordinated assault on his reputation to make money from "malicious character assassination" ... at least according to a new lawsuit.

The legendary singer filed a lawsuit claiming he's the victim of a "shockingly dishonest" and "sensational but false narrative" alleging he abandoned his kids and refused to tell his dying son Niko he loved him.

In the lawsuit, obtained by TMZ, Brian says the false narrative was cooked up by his ex-wife, Julie McKnight, and he says it's been peddled by his son Brian Jr., bloggers Marc Lamont Hill and Tasha K, and the New York Post.

In addition to the alleged defamatory claims about his last moments with Niko, Brian also claims Tasha K falsely went online and claimed he was a cheater who had sex with a minor.

Brian claims his reputation, career and his family are being negatively impacted by the alleged lies ... and he says the "relentless and persistent assault upon his character" gave him no choice but to take legal action.