Pratt and Brolin, who co-starred with Hemsworth in Avengers: Infinity War, dedicated posts to the Thor actor Saturday on Instagram.
"Happy birthday buddy!!!!" Pratt captioned a photo of Hemsworth and his wife, Elsa Pataky.
Brolin shared a video of himself singing a birthday song for Hemsworth.
"Maybe not as good as @leonbridgesofficial but Happy Birthday, man, from the deepest part of my trachea. @chrishemsworth," he captioned the clip.
"Happy birthday @chrishemsworth," Liam wrote. "I remember the first time I ever threw a knife at your head, there was this look of pure fear in your eyes. You've come a long way from that scared little kid... proud of you. You're my hero. Love u heaps and heaps."
Hemsworth spent his birthday with Pataky and their three children, 6-year-old daughter India and 4-year-old twin sons Tristan and Sasha. He shared a photo from his birthday celebration Saturday.
"Immediately after this shot was taken my son viciously attacked me from behind (due to his ninja training) and slammed my face into the flaming candles, I'll now be playing Deadpool if @vancityreynolds pulls the pin #bestbirthdayever @elsapatakyconfidential," the star wrote.