The six original cast members from Marvel's The Avengers are to participate in a Zoom hangout as part of the All-In Challenge fundraising effort.

The initiative is raising money to pay for food for vulnerable Americans affected by the coronavirus pandemic, as well as re-emphasising the need for the population to stay indoors wherever possible for the foreseeable future.

Chris Evans - aka Captain America - was nominated by Jurassic World star Chris Pratt to take part, prompting the actor to set up an Instagram account and offer a unique prize.

The lucky winner - selected randomly from people who donate to the cause - will get a private 40-minute Zoom hangout with Evans, as well as Robert Downey Jr (Iron Man), Chris Hemsworth (Thor), Scarlett Johansson (Black Widow), Mark Ruffalo (Hulk) and Jeremy Renner (Hawkeye).

"This is a great cause, this helps get food to people who are in need during this Covid nightmare, so I am very happy to be doing this," said Evans in the short video.

"Now I saw what Pratt is offering, I can't compete with that, I can't get you eaten by a dinosaur. But here's what I can offer: a virtual hang out with me and five of my closest friends: Robert Downey Jr, Chris Hemsworth, Scarlett Johansson, Mark Ruffalo and Jeremy Renner.

"We can do a private Q&A, you can ask us anything, we'll spill the beans, then maybe some games. I would recommend Scattergories."

The US is the country most affected by COVID-19, with more than 65,000 having lost their lives to date.