This image was found in a datamine and posted on the Fortnite subreddit yesterday. Also, Marshmello has listed Pleasant Park as a location for his next live show.
So far this is the only thing that confirms the event despite Epic not going public about it, other than what looks like construction of a stage on the football field at Pleasant.
So far there have been some leaks and rumors that this will be part of an LTM called “Party at Pleasant Park” with respawns on so folks can enjoy the concert without getting sent back to the lobby. But right now, that’s all rumors.
So uhh, who wants to go to a concert this Saturday?