Terrence Howard just gave a glimpse into what he said was the dark side of Hollywood ... and one example he used from his personal experience was none other than Diddy!

The film and TV actor was a recent guest on Patrick Bet-David's "PBD Podcast" ... where he claimed he was targeted by Diddy for sex under the guise of coaching.

TH doesn't say exactly when this alleged attempt by Diddy occurred ... but claims he was invited to Diddy's place when the music mogul asked Terrence for acting lessons.

Terrence claims Diddy had no material to work on -- and just "stared at me" a while before asking Terrence to play some music ... again, to just stare at him. Nothing was accomplished.

When Diddy invited him to come back over another time, TH said he realized Diddy only wanted to have sex with him. To be clear, he didn't accuse Diddy of any wrongdoing.

Terrence said a lot of people give up their "man card" to make it in Hollywood and become successful ... but he refused to do so at any point.

Needless to say, Patrick was taken aback by the story since he did not even mention Diddy ... but did ask about the darker side of the business.