She can be seen in a sound stage, lying in various poses.

The singer captioned the pic with: “A  tuna behind the scenes of our very soFISHticated @resortsworldlv 🐟💦 splash 💦🐟.”

It comes after Katy featured in a The Resorts World casino ad, alongside fellow “residency stars” Celine Dion, Carrie Underwood and her American Idol co-judge Luke Bryan.

Fans are convinced this means she is doing a Las Vegas residency

The 𝑠e𝑥y star looked incredible as a mermaid

The commercial opens with a couple waking up in their luxe hotel room before heading into a conveyor belt of food and a Faberge egg, which opens to show Katy as a mermaid under the sea.

Katy is yet to confirm the residency, but fans are convinced she will be taking to the stage in Las Vegas soon, with one writing: “Sin City then Katy?”

While this one said: “You going to Las Vegas gurrl? [sic]”

Another said: “My favorite little mermaid.”

Katy gave birth to daughter Daisy last yearCredit: EPA

Katy, who gave birth to daughter Daisy Dove with fiancé Orlando Bloom last August, will are reportedly start performing toward the end of 2021 and run through 2022.

Resorts World is the first casino to be built in Las Vegas for over a decade, and the indoor stage is expected to seat 5,000 people.

The Waking Up in Vegas singer joins a host of other stars who have had residencies in Vegas, including Jennifer “JLo” Lopez, and Britney Spears.

It’s believed Katy will be back performing in Vegas later this yearCredit: Getty

This is her first comeback to the stage since her daughter arrived into the world.

Baby Daisy, born in August 2020, has rarely been pictured, with Katy and Orlando choosing to keep their baby private.

Orlando proposed to Katy with a ruby and diamond flower design in early 2019.

The star has been open about the struggles of motherhood, and was praised for sharing candid snaps of her post-baby body

Katy also recently confessed that she’s been struggling to get any sleep since becoming a mother.

She and Orlando welcomed their baby last yearCredit: AP