Chris Hemsworth says Chris Evans will always be number 1 in his book

Captain America star Chris Evans on Saturday celebrated his 40th birthday.

Millions of his fans took to social media to extend birthday wishes to their favorite actor. 

Evan's co-stars from "Avengers" also wished him on his birthday and posted throwback photos with the actor.

Chris Hemsworth, who played Thor in Avengers, shared a picture with Chris Pratt  and wrote a funny caption that read, "Happy 40th birthday Chris Evans. You'ill always be number 1 in my book."

His caption was a reference to the first names of the three actors. 

Jeremy  Renner shared a throwback photo with Evans and wrote, "Happy 40th to you my brother!!! I mess you."