She famously wore underwear in the colours of West Ham at the MTV Europe awards in honour of her new boyfriend.
And Katy Perry got to see the team in action this week when boyfriend Russell Brand took her along to a match.
The I Kissed A Girl singer cuddled up to her man in the stands as they watched. She also posted a pic of their view on Twitter, asking fans: "Where am I?"
Katie has adopted the team as her own since getting together with Russell in September.
She missed a match earlier this month, but recorded a cover of the team's song I'm Forever Blowing Bubbles on her Twitter page in tribute.
She wrote: "For my baby who's at the game without me, I'm there in spirit."
The couple weren't the only famous faces there. Cheryl Cole was also in attendance, supporting her man Ashley who was playing for West Ham's opponents Chelsea.
Photo: © Sky