In case any of her choice cameos have left you scratching your head, here’s a breakdown of all the celebs in the ‘Swish Swish’ video…
Quite famous pop singer. Did the Super Bowl a few years ago. Once went paddle boarding with Orlando Bloom. Kissed a girl. Liked it.
Dave doesn't actually appear in the video, but he does get a credit right at the beginning.
Some of his recent music video triumphs include Kendrick Lamar's stunning 'HUMBLE.' and 'LOYALTY.', SZA's 'Drew Barrymore' and Missy Elliott's 'WTF'.
Carter went viral earlier this year thanks to a tweet he sent to Wendy's, asking how many retweets he would need to get a lifetime supply of chicken nuggets.
The teenager appears in the video eating nuggets while wearing a #NugsForCarter t-shirt. And that pooch on his lap? It's Katy's dog... Nugget.
Bill Walton and Rich Eisen
Both Bill and Rich are sports reporters, so they're appropriate choices to play commentators in Katy's 'Tigers vs. Sheep' basketball game.
Joey is the reigning world champion in the field of competitive eating. Here he is in the bleachers, chowing down on some hot dogs.
Gaten is the 14-year-old actor best known for playing Dustin in the award-winning Netflix drama 'Stranger Things'.
His hometown being listed as 'Hawkins, Indiana' is a reference to the fictional town in which the hit sci-fi series is set.
Although she's a successful Broadway star, most people probably recognise Jenna for her portrayal of Tina Cohen-Chang in 'Glee'.
Another of Katy's 'Tigers', Christine is a YouTuber, Vine star and comedian known for her collaborations with Elijah Daniel.
A plus-sized model and dancer who has become an advocate for representation of all body types in the media.
In 2015, he made his LA Fashion Week debut in a Marco Marco show, and has since appeared in a number of other fashion campaigns.
He has got a name, by the way, it's Russel Horning, and his energetic dance moves have helped garner him plenty of attention online.
Russel previously starred alongside Katy when she performed 'Swish Swish' on 'SNL', and completely stole the show in the process.
A former American football player, in more recent years Terry has turned his attention to showbiz, starring in 'Everybody Hates Chris' and presenting the US version of 'Who Wants To Be A Millionaire?'.
In 2017, he fronted the Netflix original series 'Ultimate Beastmaster', which pits contestants against each other in an intense obstacle course.
Although she's best known in the US for her six-year stint as a cast member of 'Saturday Night Live', you may know Molly for her recurring roles in shows like 'Sex And The City', 'Divorce' and 'Will And Grace'.
In 2016, she won acclaim for her role in the drama 'Other People', though her comedy work is what has brought her the most success.
Hafþór Júlíus Björnsson
Also known as 'Thor', Hafþór has competed in the World's Strongest Man competition on six separate occasions, and at the time of filming, was the reigning runner-up.
He also plays The Mountain in 'Game Of Thrones'.
West Hollywood Cheerleaders
A group of drag performers who bill themselves as "a diverse and colorful group of LGBTQI and LGBT-allied volunteers" whose main aims are "addressing social stereotypes", "promoting self-acceptance" and "ending the stigma surrounding HIV/AIDS".
One of Katy's rivals on the Sheep team, Iris is a professional bodybuilder, currently ranked as the best female in the IFBB Pro Women's Bodybuilding Ranking List.
The stars of 'Glow'
Sydelle Noel, Britney Young, Kia Stevens and Jackie Tohn all star in Netflix's latest hit series about a group of female wrestlers, bringing their colourful attire courtside in 'Swish Swish'.
An American football star, Rob is one of the most prolific players on the New England Patriots, having previously played himself in the 'Entourage' film and one episode of 'Family Guy'.
It seems he's not a fan of fictionalised basketball games.
Katy Perry's Crying Face
You may remember during her 'Witness World Wide' live-stream, Katy got rather emotional during a session with Viceland's 'The Therapist'.
Arguably the most adorable dog on the Internet, Doug has become a viral star thanks to his videos, which see him dressing up as a variety of pop culture icons.
The self-professed "fairest bitch in all the land". The generous queen, ask Miss Ellen. She is not Jasmine, she is Aladdin.
A professional dancer who has become celebrated online for her #BreakingTheStereotype movement, which encourages everyone to express themselves through dance regardless of body type, gender, race or sexual orientation.
Karl-Anthony started his career in professional basketball early, being picked for the Dominican Republic's national Olympic team when he was just 16 (although the team didn't actually qualify for the Games that year).
He's since gone from strength to strength, and was named Rookie Of The Year for the 2015-6 basketball season.