1:31 PM PT -- A spokesperson for the airline tells TMZ it cannot comment on active litigation, but says ExpressJet (partner of United) "does not tolerate racism and we are investigating this incident to better understand what occurred onboard our aircraft in December."
Nathan Davis Jr. is taking United Airlines to court because he claims he was racially profiled on a flight and falsely accused of having a gun ... according to a new lawsuit.
The TikTok star and ''Detroit'' actor just filed suit against UA, alleging he was singled out and harassed by a flight attendant late last year while he was on his way from Houston to Tennessee. Nathan says listening to music escalated to him getting removed from the flight ... for no reason at all.
According to the docs, obtained by TMZ, Nathan says he was listening to music when one of the flight attendants told him it was too loud and that others could hear it. Nathan says others were listening as well, but he was the one reprimanded.
Nathan -- who has almost 9 million followers on TikTok -- says he complied but goes on to allege the lady circled back twice more in a rude manner and continued to tell him his music was too loud -- even though he disagreed and claims she even scolded him when the music was muted.
Eventually, Nathan says she snitched to the pilot ... and that's when s*** really hit the fan. He claims the plane turned around and the staff forced him to exit the aircraft in what sounds like a humiliating display. Nathan claims the captain even tried to take his cell phone, before ultimately ordering him to go back, get his stuff and get out for good.
That's when Nathan says a gun claim was made against him over the aircraft loudspeaker ... he claims it was shocking, reckless and false.
Nathan filmed some of the encounter, and while he was leaving the plane for the second time ... you can hear someone over the PA system say "He has a gun now." He instantly reacted.
We should note -- Nathan says he wasn't even approached by law enforcement over the false and inflammatory remark. He also says no further action was taken by the airline itself ... other than bumping him up to first class on a later flight.
Now, he's suing United ... claiming negligent hiring, assault, infliction of emotional distress, discrimination and more. He's asking a judge to award him damages of no less than $10 mil.