Katy Perry shares behind-the-scenes snaps in MERMAID costume for Las Vegas hotel ad

Katy Perry, Carrie Underwood and Luke Bryan Tease Fabulous New Gigs

Katy Perry, Luke Bryan, Celine Dion, Carrie Underwood and more cut ad for new Strip hotel

Carrie Underwood, Tiësto and Katy Perry Lend Their Star Power to New Commercial for Resorts World Las Vegas