HITC Sport understands that the Magpies are hoping to tie up both deals early next week.
Newcastle agreed terms with Anderlecht early last week for the former and flew his family to the North East in a bid to persuade him to make the move to St James’ Park. And now HITC Sport understands that Mitrovic has told Newcastle that he is ready to sign for them and join Steve McClaren's side.
HITC Sport has also learned that Newcastle have made a move for DR Congo international defender Mbemba, also 20, and will pay around a combined fee of £17million - with Mitrovic worth £11million.
Newcastle would need work permits for both players but the club's hierarchy do not believe there would be many problems in gaining either. A source confirmed: "Everyone at the club was delighted with Wijnaldum but if these two young talents can come in, that would be an outstanding deal."
Newcastle have moved for Mbemba after their bid for Schalke defender Joel Matip stalled but they are also very much in the mix for Monaco's Aymen Abdennour. The 25-year-old will cost more than £15million but he is seen as the man who can take over from captain Fabricio Coloccini in the heart of their defence.