[cnn-photo-caption image= http://i2.cdn.turner.com/cnn/2010/images/06/02/art.sestak.jpg caption="Rep. Joe Sestak is picking up the endorsement of former Sen. Chuck Hagel."]Washington (CNN) – Rep. Joe Sestak, the Pennsylvania Democratic Senate nominee, is picking up an endorsement from an unlikely source: a former Republican senator from the state of Nebraska.
Chuck Hagel, a former two-term Republican senator, will announce his endorsement of Sestak on Tuesday, Sestak spokesman Jonathon Dworkin confirmed to CNN.
Hagel, who did not seek reelection in 2008 and was rumored to be a candidate for several top White House jobs after choosing not to seek the Republican presidential nomination, will announce his endorsement at two events scheduled for Tuesday in Philadelphia and Pittsburgh.
At Tuesday's events, Hagel is expected to "speak about Joe's independence and focus on doing what's right not for Wall Street or Washington special interests but for Pennsylvania's working families," the Sestak campaign said in a statement.
Both Hagel and Sestak served in the military. Hagel was twice wounded in Vietnam, and Sestak, a three-star Admiral, is the highest-ranking military officer ever elected to Congress.
Hagel is not the first moderate to endorse Sestak. New York City Mayor Michael Bloomberg endorsed the Pennsylvania congressman earlier this month.
Sestak and his Republican opponent Pat Toomey are locked in a tight battle for the Senate seat currently occupied by Sen. Arlen Specter. Sestak topped Specter in the Democratic primary.