Katy Perry has joked about becoming "fat Elvis" during her Las Vegas residency.

The 'Roar' pop star kicked off her 'Play' shows at the new Resorts World hotel in Sin City last December and she has been adding dates throughout the year, recently booking in another three-week run for October - and she has now opened up about her on/off schedule and comparing herself to a great Vegas headliner of the past - Elvis Presley.

Speaking on the 'Smartless' podcast, Katy explained: "It's three weeks on and then sometimes six to nine weeks off. It's really easy to become fat Elvis in between."

The 37-year-old singer went on to add the schedule works for her it means she's able to do the school run for her two-year-old daughter Daisy, who she shares with partner Orlando Bloom.

Katy went on: "I do it in three-week installments. It allows me the ability to drop my daughter off at pre-school, and then mommy goes to work and comes back home the next day.

"It's such a great routine. It's something that pop stars love to do and check off the box. Also, I get to create an incredible crazy, crazy show that I can't tour with because I couldn't possibly move all these absurd props that are on the stage."

During her appearance on the podcast Katy also talked about her decision to change her name at the start of her showbiz career - ditching the name Katy Hudson and adopting her mum's maiden name of Perry.

She explained: "[My name is] Katherine Hudson, people called me Katy Hudson. In the beginning, I decided not to do that.

"My mother's maiden name, Perry. [Actress Kate Hudson and I are] best friends, we get along. That was actually the first thing we got along on."