United are closing in on the signing of Ajax midfielder Van de Beek after reportedly reaching an agreement over a fee with the Eredivisie giants, who left the Dutchman out of Saturday's friendly against Eintracht Frankfurt.
Van de Beek had also been linked to LaLiga duo Barcelona and Real Madrid, but the 23-year-old Netherlands international appears set for the Premier League in a deal that could rise to £40.8million (€45m).
"Donny deserves this transfer so much," Van der Vaart told NOS. "He has played excellent for Ajax.
"And Manchester United really need this kind of player in their team. This transfer is fantastic for us [Dutch people] too.
"We are all going to follow him now. This move is so deserved."
Academy product Van de Beek has spent five seasons in Ajax's first team, accruing close to 200 appearances in all competitions for the Amsterdam outfit.
Van de Beek was one of the star performers for Ajax as they embarked upon a memorable run to the semi-finals of the 2018-19 Champions League.
He scored eight Eredivisie goals and supplied five assists in the coronavirus-hit 2019-20 season, while he managed 10 goals across all competitions.