"I think Scott Brown is with the big corporations," he says.

In contrast, Warren is "fighting for people who are up against it."

"She got heart, she got guts and she’s not gonna back down," he says.

Warren's campaign released the ad just days after a Boston Globe report revealed that Democratic leaders in Massachusetts have expressed concern that Warren's ads, up until now, have done a poor job of selling her personality to voters and often made the candidate come across as stiff and preachy.

And that's exactly the perception Brown's campaign has tried to cultivate throughout the race so far. In contrast, one of Brown's greatest assets is his likability in the state and how easily he interacts with voters during campaign stops.

Brown often mentions his truck — and can be seen driving it in campaign ads — as a way to connect with just the white working-class voters that make up so much of Massachusetts' electorate. And his campaign rarely misses an opportunity to call Warren as "the Harvard professor," an attempt to make her seem elite and out-of-touch.

The Boston Globe report indicated that Democrats are worried the Brown campaign's strategy had been working because Warren has been unable to pull ahead in the polls thus far despite the fact President Obama leading Republican Mitt Romney by double digits in Massachusetts. 

Warren's advisers, according to the report, were considering shifting their media strategy to ads showcasing voters and humanizing Warren.

This new ad attempts to do just that, and the gym functions on the same level as Brown's truck — it offers a way for Warren to connect to blue-collar voters. The ad could mark the beginning of a new strategy in Warren's campaign focused on combating Brown's likability advantage.

Brown, in response to the ad, accused Warren of running a campaign "that tears people down," as indicated by this new ad -- which he said was a sign of hypocrisy on Warren's part, as she has claimed "not to like attack ads."

"Her misleading and untrue attacks against me are a sign of desperation from an increasingly desperate and flailing campaign," he said."

Watch the ad:

--This post was published at 3:26 p.m. and updated at 5:53 p.m.