It's been over one year since a young Scottish boy with a rare disease asked for help from Iron Man, his favorite superhero. Now, Robert Downey Jr. is stepping up to answer the call to action.

Aaron Hunter is a 7-year-old boy from Alexandria, Scotland who suffers from ROHHAD syndrome: a rare and incurable disease that causes the person's organs to malfunction and fail.

Back in 2017, the ROHHAD Association granted Aaron a wish that he used to ask for Iron Man's help in raising awareness for the debilitating disease. The youngster then made a video for the charity organization's social media page explaining his situation and calling the Hollywood star to action.

When the video went viral, Downey Jr. reached out to Aaron to see what he could do to help with the cause. In addition to raising awareness for ROHHAD syndrome on social media over the course of the last year, Downey Jr. made a video earlier this week that is bound to make a huge difference for the disease.

In the video, Downey Jr. says that his charity organization Random Act Funding will be holding a contest to raise money for ROHHAD syndrome research.

For every $10 donated to his Crowdrise campaign, contest participants will have a chance to attend the World Premiere of Avengers: Infinity War in Los Angeles with Downey Jr. on April 23rd.

Not only that, but the winner will be flown from anywhere in the world to Hollywood, California; stay for two nights at a four-star hotel; and be invited to the after party.

The contest ends on April 13th, so be sure to get those donations in soon.

(WATCH the A-lister's call to action below)

A post shared by Robert Downey Jr. (@robertdowneyjr) on Mar 13, 2018 at 9:03am PDT

A post shared by Robert Downey Jr. (@robertdowneyjr) on Mar 13, 2018 at 9:03am PDT

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