Mark Wahlberg, Brendan Karate Boston Celtics The Fighter

Yesterday we caught Mark Wahlberg taking his oldest son Michael to karate in Brentwood, and the beefy star wasn't in the mood to smile, but given how good he looks in a tight tee-shirt, we're willing to forgive him! And it looks like his four-year-old son has already learned a few of his signature tough guy poses ... so cute!