Lady GaGa is to join U.S. Tv and radio mogul Ryan Seacrest as co-host of his weekly syndicated American Top 40 chart countdown show this weekend (05-06Apr14).

The pop star will take calls and questions from fans as part of the promotional campaign for her upcoming album Artpop.

Gaga will wrap up her historic seven-night concert stint at New York's Roseland Ballroom on Monday night (07Apr14). The fabled venue will shut its doors for the last time after the singer's final show.