The 'West Wing' star - who was a member of the acting 'Brat Pack' in the 1980s - was rehearsing a fight scene with the actor and accidentally hit Tom For Real, leading to his co-star to retaliate with such force that they had to be pulled apart.
Rob - who appeared in the 1983 movie 'The Outsiders' with the Hollywood star - said: "We all beat the living s**t out of one another. We really did. I got one clean shot on Tom, and Tom is such a competitive lunatic - which is what I love about him - but the next thing you know he's ready to kill me!
"We were all competitive. It wasn't just Tom. We were hardcore. But Tom. Listen, he was up for my part and I thought he was going to get it. And Tom's Tom. He's a whole lot of guy. It's like the United States and China right now. If you treat China like a foe surely she will become one. It was all good. But he was the one I was worried about."
After roles in 'The Outsiders' and 'St. Elmo's Fire', Rob found himself transformed into a megastar despite barely being out of his teens and he admits his sudden rise to fame led to him partying too hard.
When he was shooting 'Illegally Yours', which was released in 1988, Rob was romancing Princess Stephanie of Monaco and he admits he can look back on that moment and realise he was letting his career slip.
The 47-year-old actor - who has just released his autobiography 'Stories I Only Tell My Friends' - added to the Daily Telegraph newspaper: "Only in hindsight do you go, 'This is the beginning of the end. I should have known'. I was out gallivanting with a princess while the movie I was supposed to be doing was completely falling apart.
"My eye was not minding the store at all. I had nobody in my life who was doing it, which is what our good friend Mr. Cruise never stopped doing. Never, ever, ever. He had the ability to say, 'I'm making a movie right now, I'm playing a character, so you need to go away while I do this.' He has that ability."
In 1988, Rob was involved in a sex scandal when a videotape emerged of him having sex with two women, one of whom was 16.