The Portland Symphony Orchestra and The Mallett Brothers Band will help the Yarmouth Clam Festival celebrate its 50th anniversary this summer with a free performance at 7 p.m. July 18.

The stage that will be erected on athletic fields behind Main Street and Route 1.

Singer-songwriter Dave Mallett will perform with The Mallett Brothers Band, which features his sons Luke and Will Mallett. They will join the orchestra for several songs. The performance will end with a fireworks display.

More than 100,000 people attend the festival, which raises money for local nonprofits.