Mitt Romney will head to Arizona next week to campaign for Sen. John McCain's reelection.

The two will appear at a town hall meeting in Mesa, Ariz., next Friday, according to McCain's campaign website.

In 2008, the competition between the two presidential candidates at times turned bitter. But Romney dropped out of the race before many had expected and gave his endorsement to the Arizona Republican.

McCain is squaring off against Tea Party favorite J.D. Hayworth.