Actor Robert Downey Jr is requesting all his fans to attend the world premiere of Marvel's Â`Avengers: Age of Ultron" and help his charity to donate for children who are suffering from terminal illnesses.

The 49-year-old in his latest post on his Facebook page requested his fans to donate to a charity event that is supporting Julia's House, that provides care and support for life-limited children and their families.

Â`Hi folks, hereÂ's the skinny: weÂ've raised $1.3 MILLION for kids with terminal diseases. ThatÂ's incredible, but I think we can do better.

Â`Our goal is to reach $2M to help build a brand spanking new wing for JuliaÂ's House. ThereÂ's just ONE WEEK left to enter to win the chance to go to the premiere of 'MarvelÂ's Avengers: Age of Ultron' with me. Click the pic and ASSEMBLE," said the Â`Avengers: Age of UltronÂ` star, according to a statement.

Marvel Studios is presenting Â`Avengers: Age of UltronÂ`, the follow-up to the biggest superhero movie of all times.

The film's cast includes Chris Hemsworth, Mark Ruffalo, Chris Evans, Scarlett Johansson and Jeremy Renner.

The movie is written and directed by Joss Whedon, produced by Kevin Feige and is based on the popular Marvel comic book series Â`The AvengersÂ`, which was first published in 1963.

The movie is slated to release on April 24.