The two clubs are believed to be agreeing a compensation fee of around £600,000.
The 16-year-old winger, dubbed the ‘next David Beckham’, is highly regarded by the Belgium club but has rejected all offers from the club.
The Belgium, with Serbian descent, has been tracked by a string of European clubs including Chelsea, Manchester City and Inter Milan.
But he has agreed terms to join Manchester United, leaving the clubs to discuss a fee.
Anderlecht general manager Herman van Holsbeeck confirmed Januzaj is heading to United but bemoaned the rules allowing this deal to happen.
“We are in negotiations,” he said to HNB.
“It is going in the right direction, there is no agreement yet, but I think the player will be going to Manchester.”
“We are negotiating a fee higher than the compensation just for training.
“We made a good financial offer. We also said he would be part of our first-team by the 2012-13 season, but Januzaj refused,” Van Holsbeeck added.
“Have Anderlecht lost a star? Only the future will tell us. He is not ready for the first-team, but how many are at 16?
“He does have potential and he had the profile to become a good player at Anderlecht.
“But alas, we do not have that choice, his parents and those around him have decided otherwise – we can only accept it as the regulations are made this way, we are powerless.”
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