Diddy's former makeup artist claims she overheard him abusing Cassie ... 6 years before the now-viral hotel hallway incident.
Mylah Morales -- who says she worked with Diddy and Cassie for years as their primary MUA -- spoke with CNN's Laura Coates Thursday, stating she heard the Bad Boy Records founder assault his ex-girlfriend in 2010 ... and that it allegedly left Cassie with a black eye.
According to Mylah, she saw Diddy and Cassie enter a hotel room, where they proceeded to get into a heated argument.
She added ... "Whatever was going on in there I don't know, but all I could think of was to grab Cassie's things and start packing it up and just getting her out to safety and bringing her to my house."
Mylah recalled Cassie coming out of the room looking "badly beaten," claiming she had a black eye, a busted lip and knots all over her head.
The makeup artist says she and Cassie did not go to the police after the incident ... out of fear of Diddy.
She continued ... "Puffy's a very powerful person and we were quite terrified. I just brought her to my house and my friend, who is a doctor ... treated [Cassie] to make sure she didn't have a concussion."
Mylah said it was painful to see Cassie in such pain. Aside from her recollection, Mylah did not offer any additional corroboration of the alleged incident during the interview.
This update comes almost 2 weeks after footage from 2016 surfaced of Diddy beating Cassie in the hallway of a Los Angeles hotel. Diddy has since apologized for the incident, calling it one of "the darkest times in [his] life."