Mark Wahlberg is PUMPED his New England Patriots signed James Harrison -- and he made a video straight from his boat welcoming the ex-Steelers star to the squad.
"Did you hear the news?" Wahlberg asked his wife, Rhea ... "James Harrison is a Patriot? Oh my. Defense just got a lot better."
He added, "Isn't it nice that [Tom Brady] got away without getting hit by him in the playoffs and possibly the AFC Championship?"
"Go Patriots. Go James Harrison."