The Rolling Stones have been bringing in friend after friend to join them on stage for their “50 and Counting” tour—as if Stones shows aren’t exciting enough already. Big name country music star Brad Paisley will be the one to join the Stones this time when they play at the Wells Fargo Center in Philadelphia on June 18. Other guests have included Arcade Fire vocalist Win Butler on “The Last Time,” Tom Waits on “Little Red Rooster,” Katy Perry on “Beast of Burden,” Taylor Swift on “As Tears Go By,” Sheryl Crow on “All Down the Line” and Dave Grohl on “Bitch.” Last night, Gary Clark Jr. had the honor of taking on “Going Down” with the band in Boston’s TD Garden. They have another show in TD Garden tomorrow. The Stones will also be heading to the Verizon Center in Washington, D.C., on June 24.