The 40-year-old Toxic singer has been sharing a number naked photos of herself enjoying holidays by the beach and celebrating her body on social media of late, since being officially freed from the legal control of her family.
Katona, 41, wrote in her New! magazine column: "Britney Spears has been posting a string of Instagram pictures of herself on the beach completely nude.
"She needs to save them all and get on OnlyFans! She could make a fortune doing that rather than sharing them on social media for the world to see."
She added: "Britney, you need to sign up and use my referral code!"
Spears recently posted a picture of herself topless on the beach captioned: "Planning on having babies in Polynesia."
She announced last year she is engaged to her personal trainer boyfriend Sam Asghari.
During her court battle to end her conservatorship after 13 years, she told a judge: "I want to be able to get married and have a baby."
The ...Baby One More Time singer is mother to sons Sean, 15, and Jayden, 15, with ex-husband Kevin Federline. The couple split in 2006 and he has 70% custody of their children.
Katona — who charges fans £19.99 per month to subscribe to her account — recently told The Sun that OnlyFans had made her a millionaire.
The Atomic Kitten singer, who started out as a Page 3 Girl, said: "People are quick to say, 'She's desperate' if I get out a bit of nipple, but I've made my first million since bankruptcy and I'm so, so proud. If it wasn't for OnlyFans I wouldn't have had money to invest in myself and in making more companies."
The reality star and mother-of-five was declared bankrupt in 2008 and again in 2013, and so turned to selling explicit pictures of herself.
She previously revealed: “I just send sexy messages and pictures, but nothing more than topless.
"I’ve had loads of requests for foot selfies from people with foot fetishes."
The singer is mother to daughters Molly, 20, and Lilly, 19, from her marriage to Brian McFadden, as well as daughter Heidi, 15, and son Max, 13, from her second marriage to Mark Croft. She also has seven-year-old daughter Dylan-Jorge from her relationship with late husband George Kay.
Katona is engaged to 34-year-old personal trainer Ryan Mahoney, who she met on dating app Bumble in 2018. He proposed in August 2020.
Watch: How Britney Spears' nails helped with her anxiety