Marvel has yet to give any confirmation about “Iron Man 4” and speculations are brewing that Robert Downey Jr. may not be in the fourth installment of the franchise.

In an interview with Variety in 2014, Downey laughed off the idea when asked if he would “let” somebody else play Tony Stark.

“I like that the idea is that it would be up to me, like I’m casting director for Marvel,” he said.

Although it seems RDJ is irreplaceable as Tony Stark. However, if this happen, who could possible replace his role as billionaire, playboy and philanthropist superhero?

1. Ty Simpkins

The 14-year-old actor has been rumored to replace Downey in “Iron Man 4”.

Although Simpkins portrayed Harley Keener impressively in the third “Iron Man” film, Cinema Blend noted that many are still not sold to the idea of another actor taking the role.

Ty’s role in “Iron Man 3” gave him the nomination for Best Performance by a Younger Actor at the Saturn Awards.

Reports said “Iron Man 4” is expected to be released in 2020 and the earliest time of production is in 2018. By then, Simpkins is already 17.

2. Leonardo DiCaprio

Movie Web wrote DiCaprio looks more like Tony Stark than RDJ, and the 38-year-old award-winning actor has proven himself very capable of playing cocky characters.

Leo has yet to play a superhero or become part of any Disney movie. If DiCaprio wanted to take part in this type of films, there wouldn’t be a better role for him than “Iron Man,” Movie Web noted.

3. Jon Hamm

The role of “Iron Man” would bring Hamm gentlemanly demeanor and arrogant attitude to a wider demographic.

Movie Web said the “Mad Men” actor might be one of the few stars that could pull off the alcoholism aspects of Tony Stark in an intelligent, humorous manner.

4. Colin Farrell

Farrell might be an unconventional choice, but Movie Web noted Marvel’s choices seem to be unconventional most of the time.

Colin knows how to be cocky yet lovable, which most likely a casting director will look for an actor that will fill the shoes of Stark.

5. Luke Evans

Movie Pilot thinks Evans is a really good actor and he actually looks like RDJ a lot.

Evans has an experience playing a hero-like role in 2010’s “Clash of the Titans” as Apollo.

Meanwhile, Downey will appear in the upcoming Marvel’s “Captain America: Civil War,” which is set to roll in cinemas on May 6, 2016.