1:52 PM BST
Sam MarsdenBarcelona correspondent
However, Van Gaal will only be in charge for one match next season, with Telstar offering supporters the chance to be his assistant.
"It's happening!" Telstar announced on Wednesday. "Van Gaal will return to coaching next season for one league game only -- and you can be his assistant!
"We are running a lottery for the chance to sit next to the Champions League winner on the bench at the BUKO Stadion. Money raised will go towards the Spieren voor Spieren Foundation."
Telstar finished 13th in the second tier of the Dutch football pyramid last season. They are coached by Andries Jonker, who previously worked as Van Gaal's No.2 at Barcelona and Bayern Munich before taking on a role at Arsenal's academy.
Van Gaal, 69, spent one season at Telstar as a player in 1977-78 before embarking on a successful career in management.
Upon leaving United in 2016, when he was replaced by Jose Mourinho, Van Gaal announced that he was taking a sabbatical from football.
Three years later, in 2019, he announced his retirement from all football-related activity.
"I am a pensioner now," he told Dutch TV show VTBL. "I have no ambition to be a technical director or a TV pundit.
"My wife Truus gave up her job for me 22 years ago and followed me when I went abroad. I told her I would quit as a coach when I turned 55, but instead kept going until I was 65."