Republican Gabriel Gomez and Democrat Edward Markey are prepping for their final debate in Massachusetts' special U.S. Senate election.

The candidates go head-to-head in an hour-long debate tonight at the studios of WGBH-TV. The debate is sponsored by a Boston media consortium.

The match-up comes as Gomez is struggling to close a gap with Markey who has held a modest lead in recent polls.

Gomez has portrayed Markey as an entrenched Washington insider while Markey has cast Gomez as beholden to the national Republican agenda.

Markey headed into the final stretch with more than a two-to-one fundraising advantage over Gomez.

Markey's latest campaign finance report shows as of June 5 he had nearly $2.3 million to spend compared to just under $1 million for Gomez.

The election is June 25.