Pop stars Kelly Clarkson and Lady GaGa will team up for a special show at the House of Blues on Monday, May 4 as part of the second "Grammy Celebration Concert Tour" presented by T-Mobile Sidekick and the The Recording Academy. Tickets for the show are free, but the only way to get them is through T-Mobile.

Fans can enter through the T-Mobile's website, here, or at giveaways at local stores beginning on April 20. Those tickets will only be available at two locations: 375 Washington Street in Boston and at the South Shore Plaza in Braintree. At the in-store promotions, which will run though May 2 or while supplies last, fans will have to either purchasing a Sidekick, showing their existing Sidekick, or play a special game.

Clarkson is supporting hew new release, All I Ever Wanted. The album, her fourth studio release, debuted at number 1 on the Billboard 200. "My Life Would Suck Without You," the new album's first single, topped the Billboard Hot 100 earlier this year. "I Do Not Hook Up," the album's second single, was jut released to radio.

Lady GaGa continues to back her 2008 debut album, The Fame. The album peaked number 4 on the Billboard 200. She is currently on her first headlining tour (which stopped in Boston last month) after previously opening for various acts including Boston's New Kids On The Block.