Pop star Los Lady Gaga is to join Amercian TV and radio mogul Ryan Seacrest as co-host of his weekly syndicated American Top 40 chart countdown show this weekend.

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

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