Man Utd have signed Serb pair Zoran Tosic and Adem Ljajic from from Partizan Belgrade but the latter will not arrive immediately.
The double deal has been the subject of a number of twists and turns over the last month but terms have now been agreed and the deal has gone through.
Tosic, 21, has 12 full international caps to his name and is a gifted left winger who will challenge the likes of Ji-Sung Park, Nani and Ryan Giggs.
Under-21 star Ljajic, 17, will continue to learn his trade with Partizan for the rest of the season when the attacking midfielder's situation looks set to be addressed again.
Unconfirmed reports claim United could eventually pay £17m for the pair if they are successful during their United careers.
Tosic and Ljajic will join fellow Serb star Nemanja Vidic in the United squad.
Read more about Manchester United.