Elizabeth Olsen and Paul Bettany, who play Scarlet Witch and Vision in the superhero spectacular, are reported to be heading for the city more than two weeks ahead of the movie’s release.
Co-director Joe Russo is also said to be confirmed for the special event, which will allow attendees to see the spectacular opening sequences of the film, which is expected to be one of the biggest box office sensations of 2018.
He and his brother Anthony Russo have already teased fans over the prospect of Avengers stars descending on the city by telling the city to “get ready” in response to an online campaign calling for Edinburgh to host a gala premiere.
The Edinburgh International Film Festival and its patron Karen Gillan, who is also in the new blockbuster, have already thrown their weight behind the campaign launched by Stirling-based fan Mae Trumata.
The opening 20 minutes of the movie are thought to be partly set in Edinburgh where six weeks of filming was carried out last year.
An exclusive post-screening cocktail party and intimate dinner are reported to have been lined up for the sneak preview events in Edinburgh and London.
However Disney chiefs insisted they were still finalising their plans.
Last year Joe Russo hailed Edinburgh as “one of the most cinematic cities I’ve seen” and said he was shocked more movies had not used it as a backdrop.
He added: “I’ve been fortunate enough to travel to Edinburgh a few times over the last few years and I just loved the city.
“I find it one of the more beautiful cities in Europe. It’s amazingly well-preserved, the architecture is stunning and we had an idea for a sequence that we thought would pair very well with the city.”
Details of the preview screenings were leaked as a new trailer showed Scarlet Johannson’s Black Widow character taking part in a dramatic battle sequence in Waverley Station, where a vast temporary set was built for the production, near the station’s Calton Road entrance.
New footage has also emerged of Scarlet Witch and Vision in the station, which was transformed for filming of the movie due out at the end of April.
It emerged earlier this week Edinburgh is expected to provide the backdrop to a dramatic attack by Black Order assassins on Scarlet Witch and Vision only for Captain America, Black Widow and Falcon to ride to the rescue.
Footage has emerged of dramatic explosions against the backdrop of the City Chambers on the Royal Mile.
The biggest ever movie production to be shot in Scotland, Avengers: Infinity War is estimated to have generated £10 million to the city’s economy during the seven weeks of filming, along with several months of pre-production.
It emerged earlier this year that the film’s superheroes have helped more than double the value of film and TV productions to the city in the space of a year, along with the filming of new feature film biopics of Robert the Bruce and Mary Queen of Scots.
More than 400 crew members worked on the filming of Avengers: Infinity War, which also stars Robert Downey Jr, Chris Evans, Chris Hemsworth, Mark Ruffalo and Anthony Mackie.
However tourism bodies and city leaders are gearing up for unprecedented spin-offs from fans keen to flock to the various locations featured in the movie.
Rosie Ellison, manager of the Film Edinburgh commission, which handles enquiries from film and TV productions, said: “We worked extensively with the production team for Avengers: Infinity War to support them in filming across the city last year, so we are very excited to see the Edinburgh on the big screen when the film opens next month.
“We’ll be celebrating by encouraging fans to come to Edinburgh to see it during opening weekend and enjoy the ‘city of superheroes.’”
Kate Campbell, economy convener at the city council, said: “The movie is the largest production Edinburgh has ever hosted, and it is a real credit to the city that the feedback from Disney’s producers, directors and actors was all so positive and that they loved the city so much they might well return. Edinburgh is getting ready to roll out the red carpet
“You can really feel the excitement building for the movie’s release, with a whole weekend of superhero activity being planned as businesses capitalise on the buzz surrounding the city’s starring role.”