Sen. Scott Brown, the Massachusetts Republican who paid for law school by posing shirtless for a Cosmopolitan magazine photo shoot, thanked God that his Democratic rival Elizabeth Warren never did the same.

On a Boston radio show Thursday, Brown was responding to a comment Warren made at a Democratic primary debate this week about paying for her tuition bills, telling the crowd I kept my clothes on.

Thank God, Brown said after the radio host repeated Warren's comment.

Brown is gearing up for a highly-competitive reelection campaign against Warren. In the interview, he defended his decision to pose for Cosmopolitan, taking swipe at Warren, a Harvard Law professor and consumer advocate.

Bottom line is, I didn't go to Harvard. I went to the school of hard knocks. I did whatever I had to do to pay for school, Brown said. Let her throw stones, I did what I had to do.

Poll: Brown, Warren Tied

A poll from UMass Lowell/Boston Herald poll showed the two candidates in a statistical dead heat. Though Warren must get through the Democratic primary, she is the early favorite to clinch the nomination.

Since that poll, Brown gave a speech on the Senate floor decrying partisanship and gridlock, a likely effort to reach out to moderates and a major bloc of Massachusetts voters who are unaffiliated. (Watch a video of Brown's speech here.)

Another hitch for Brown is his waning support for the Tea Party groups that helped him win a Senate seat in deep-blue Massachusetts in 2010, according to a report from The Daily Caller.

One Bay State Tea Party organizer said Brown had disappointed us a few times and suggested that similar groups may avoid heavy campaigning.

Listen to Brown's interview with a Boston radio show by clicking here.