www.youtube.com/watch?v=ysTh7eQlCTw

Massachusetts Sen. Scott Brown (R) began airing a new ad today, featuring former Boston Mayor Ray Flynn, a Democrat.

“Scott Brown is a person that I have great admiration for,” Flynn says to the camera, sitting in his living room. “I’ve found him to be a regular guy: honest, hardworking. He’s also an independent voice,” he adds, as b-roll of the Senator appears on screen.

“I’m a Democrat, but I’m tired of all the polarization, the pettiness, the bickering,” says Flynn, who served as mayor of the Bay State’s capital from 1984 to 1993. “Scott Brown is a person that you can work with. I mean, I’ve been involved in politics for almost 50 years. That’s the name of the game, electing people you can trust. I think that person really is Scott Brown.”

A source familiar with the buy said the ad was backed by $426,000 on broadcast and cable television statewide, today through Aug. 5. There was also a $25,000 buy on WJAR, the NBC affiliate in Providence, R.I., which reaches a chunk of southeastern Massachusetts, from Aug. 6 through Aug. 12.

Brown is locked in tight race with Democrat Elizabeth Warren, a Harvard professor and consumer advocate. In a state that will vote for President Barack Obama, Brown has worked to position himself as a solutions-oriented, independent Senator. Ads like this one would appear to help burnish his bipartisan credentials, especially with an important swing block of blue-collar voters.

Roll Call rates the Massachusetts Senate race as a Tossup.