The 42-year-old actor - who stars in new movie 'Lone Survivor', based on the memoirs of Navy SEAL officer Marcus Luttrell - is offended by Hollywood stars who complain about the rigorous training they have to do for their movies and believes it's nothing compared to real warfare.
Speaking at his film's premiere on Tuesday, the impassioned star ranted: "For actors to sit there and talk about 'Oh, I went to SEAL training' ... I don't give a f**k what you did. You don't do what these guys did. For somebody to sit there and say my job was as difficult as being in the military? How f**king dare you, while you sit in a makeup chair for two hours.
"I don't give a s**t if you get your ass busted. You get to go home at the end of the day. You get to go to your hotel room. You get to order your f***ing chicken."
Mark's heated speech came after he was questioned about how he trained for his role in the army film during on an onstage Q&A, and his response took many of the audience members at the premiere by surprise, reports E! News.
The actor attempted to regain his composure and apologize, saying: "I'm sorry for losing my s**t. Don't ask any more questions tonight."
Why Martin McGuinness will be remembered for hundreds of years to come