Van Hecke, who celebrates his 20th birthday today, only broke into NAC’s first team in December, but has impressed.
And talent-spotters Monaco have seen enough, clinching a deal to sign him from the Eerste Divisie side.
The centre-back’s move is thanks to NAC technical director Tom Van Den Abbeele, who has good relations with Monaco.
It is doubtful that Van Hecke will play in Ligue 1 next season, with a loan move almost certain.
Utrecht offered €1m for Van Hecke this spring, so would welcome the chance to sign him on loan.