Zac Efron is Team USA's Biggest Fan at the Olympics!

Zac Efron hangs out with friends poolside at his hotel on Wednesday (August 17) in Rio de Janeiro, Brazil.

The 28-year-old Neighbors 2 actor flew to Rio to support team USA during the Olympics.

PHOTOS: Check out the latest pics of Zac Efron

Zac landed in Rio earlier this week to surprise Simone Biles and the girls of the US gymnastics team and congratulated them on their big wins in Rio.

After relaxing at his hotel, Zac attended a basketball game where he shared a selfie supporting team USA.

“US all day #rio2016,” Zac captioned the below Instagram pic.

20+ pictures inside of Zac Efron relaxing in Rio…