Iron Man star Robert Downey, Jr. is planning to celebrate his upcoming birthday by hosting a special screening of the new Captain America movie for 50 lucky children.

The Hollywood actor will turn 49 on 4 April (14), but instead of throwing a lavish bash for himself, he has decided to treat a group of young superhero fans to a big party instead.

He tells, "I'm having 50 kids over and I'm screening Captain America 2 on my birthday, which happens to be the day it opens (in America)."

Downey, Jr. admits he has yet to see his The Avengers co-stars Chris Evans and Scarlett Johansson in Captain America: The Winter Soldier, but he is looking forward to having his own private premiere - thanks to being a part of the Marvel comics family.

He says, "That's one of the perks of being on the inside track at Marvel."