(CNN) - Bill Clinton's heading to Washington State to help out a fellow Democrat fighting to keep her Senate seat.
The former president will team up with Sen. Patty Murray at a rally in Everett, Washington, on October 18, according to a release from the Murray campaign.
President Obama joined Murray in Washington State last month, and Vice President Biden's expected to make the trip next month.
The three-term senator is facing a difficult re-election this year against Republican challenger Dino Rossi. The most recent polls of likely voters in Washington State, including a CNN/Time/Opinion Research Corporation survey, indicate that Murray holds a single digit lead over Rossi, the state's 2004 and 2008 GOP gubernatorial nominee.
"President Clinton has always been a strong advocate for middle class families – the ones who work hard and play by the rules – and I am proud to stand by his side as we work on building a stronger America to help those families succeed," Murray said in a written statement.
The former president's been very active on the campaign trail this election cycle. Earlier this month he traveled to Ohio to help out Gov. Ted Strickland, to Pennsylvania to campaign with Rep. Joe Sestak, the Democratic Senate nominee, and to his native Arkansas to team up with embattled Sen. Blanche Lincoln.
Next month he also heads to California to campaign with an old party rival, Jerry Brown. The California attorney general - now the party's gubernatorial nominee - is in a tough battle with GOP nominee and billionaire businesswoman Meg Whitman.
–Follow Paul Steinhauser on Twitter: @psteinhausercnn