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Numb3rs star Dylan Bruno will guest-star in the final two episodes of NCIS' seventh season, TVGuide.com has learned exclusively.

Check out photos of the NCIS cast

Bruno will play Lt. Jason Paul Dean, a freelance mercenary with ties to the private military company operated by Col. Merton Bell (Robert Patrick

), an enemy of Gibbs (Mark Harmon). As we first reported, Lt. Dean is an imposing, edgy and dangerous former Army Ranger who was highly decorated before a screw-up in Afghanistan led to his dishonorable discharge — and he's not at all afraid to kill when necessary.Obviously, that's bad news for Gibbs, who arrested Bell for going after the granddaughter and daughter-in-law of Gibbs' good friend, Mike Franks (Muse Watson), earlier this season. Since then, Bell has also sent sly lawyer M. Allison Hart (Rena Sofer) after Gibbs. Will Lt. Dean be more successful?

Rena Sofer keeps NCIS secrets by not knowing what they are

Bruno's character will first appear in the season's penultimate episode, but he will stick around for the big finale, in which Gibbs has to make a devastating choice to save his team.Bruno, best known as FBI agent Colby Granger on Numb3rs, has also appeared on CSI: Miami and in Saving Private Ryan.

See photos of Bruno throughout his career

NCIS returns with the first of five new episodes Tuesday, April 27 at 8/7c. The season finale airs Tuesday, May 25 at 8/7c.Are you excited to see Bruno's character mix it up with Gibbs?