Lisandro Martinez will take the No 6 shirt at Manchester United while fellow new signing Christian Eriksen will wear No 14 at Old Trafford.
Argentina international Martinez, whose £55million transfer from Ajax was completed earlier this week, takes the number vacated by Paul Pogba, who has moved back to Juventus.
The likes of Gary Pallister, Jaap Stam and Wes Brown have worn the No 6 shirt at United in the past couple of decades.
New Manchester United signings Christian Eriksen (left) and Lisandro Martinez (right) have been allocated the No 14 and No 6 shirt numbers respectively at Old Trafford
Danish star Eriksen, who was snapped up by Erik ten Hag after he left Brentford, will take the shirt formerly worn by Jesse Lingard.