Lukasz Plonowski played with Youri Tielemans at Anderlecht.
Tielemans made his debut at 16 years of age and has never looked back, making over 100 appearances for the first team side, now still only 19.
He is considered one of the brightest young prospects in world football and has continuously been linked to plenty of the top clubs.
Mourinho appears to have added Manchester United to that list.
Plonowski told Weszlo: "Youri called me up recently and said: 'Lukasz, you know who called me? Mourinho. He asked if I would take the opportunity to move to Manchester United.”
"He has promised to be a great talent from the beginning.
"He is barely 19 years old, but they are wondering whether to put him in the Belgian national team.”
If United were to go through with this deal, it would surely have a view to the future, rather than this campaign.
Mourinho has already made a huge statement in this summer’s transfer market signing Eric Bailly, Henrikh Mkhitaryan, Zlatan Ibrahimovic and breaking the world record transfer fee for Paul Pogba.
They have been added to a squad that already possessed enormous potential with the likes of Marcus Rashford, Timothy Fosu-Mensah, Luke Shaw and Anthony Martial.
If highly-rated Tielemans was to make the move to Old Trafford, he would only cause the future of United to look even more promising.