The 'I Kissed A Girl' hitmaker – who is engaged to Russell Brand – topped the annual Maxim Hot 100 list for being "sexy and talented", narrowly beating Victoria's Secret model Brooklyn Decker and 'Avatar' actress Zoe Saldana into second and third place respectively.
Explaining her top ranking, the US men's magazine said of Katy: "She's the best friend you suddenly realize you've loved your whole life. The rad chick who taught you to skateboard and whistle and also looks unbelievable in a bikini."
Making up the rest of the top five were 'Gossip Girl' star Blake Lively, and 'Transformers' beauty Megan Fox, while 'Russian Roulette' singer Rihanna, George Clooney's girlfriend Elizabetta Canalis, actress Olivia Munn, socialite Kim Kardashian and model Marisa Miller made up the rest of the top 10.
Last year's Maxim Hot 100 number one Olivia Wilde scraped in at number 20, while notable absentees included Beyonce Knowles and Lady Gaga.
Maxim Hot 100 Top 20:
1. Katy Perry
2. Brooklyn Decker
3. Zoe Saldana
4. Blake Lively
5. Megan Fox
6. Rihanna
7. Elisabetta Canalis
8. Olivia Munn
9. Kim Kardashian
10. Marisa Miller
11. Eva Mendes
12. Audrina Patridge
13. Amber Heard
14. Scarlett Johansson
15. Amanda Bynes
16. Selita Ebanks
17. Leighton Meester
18. Christina Aguilera
19. Bar Refaeli
20. Olivia Wilde