Robert Downey Jr. Turns 50 Today!
Credit: Jason LaVeris/FilmMagic

Happy birthday, Robert Downey Jr.! The actor, more recently know for his role as Marvel superhero Iron Man, rings in his 50th birthday today—and he has a lot to celebrate.

Downey made his debut at the age of 5 in the film Pound, which was written and directed by his father, Robert Downey Sr. The actor and producer has been in the industry for more than four decades, and has topped the Forbes list of the highest paid male actors. Working with everyone from Gwyneth Paltrow to Jude Law, his recent film credits include Sherlock Holmes: A Game of Shadows, The Avengers, Iron Man 3, and The Judge.

This year, fans can catch the star in Marvel's Avengers: Age of Ultron, in theaters May 1. In honor of Robert Downey Jr.'s birthday, we're taking a look at celebrities who keep getting better with age.