John McCain is calling in former Massachusetts Gov. Mitt Romney on Friday.
McCain and Romney are scheduled to appear together at a town hall meeting in Mesa.
Romney’s visit to Arizona marks his second time stumping for McCain. The two Republicans also campaigned together in March while Romney was in Phoenix for a book signing.
Romney and McCain were bitter rivals for the Republican nomination for president in 2008. But Romney aggressively campaigned for McCain in the general election and has endorsed the Arizona senator in his re-election bid.
McCain is facing a tough primary challenge from former U.S. Rep. J.D. Hayworth.