United reached an agreement with the French outfit for the acquisition of the highly-rated youngster, who also had strong interest from Real Madrid.
A youth international with the French national team, Leny Yoro is just 18 years old and made his first-team debut for Lille in the 2021/22 season. However, it was during this campaign under Paulo Fonseca that he made his mark, appearing 44 times.
"Signing for a club with the status and ambition of Manchester United so early in my career is an incredible honour. From the very first conversations with the club, they've outlined a clear plan for how I can develop in Manchester as part of this exciting project and they've shown great care for me and my family," Yoro said.
According to reports in England, Manchester United paid 62 million euros to sign the player, who will replace his compatriot Raphael Varane in defence. The deal could also rise to 70 million euros.
Sporting director Dan Ashworth was full of praise for the young defender.
"Leny is one of the most exciting young defenders in world football, he has all the attributes needed to be a world-class centre-back. Having such a bright start to his career, we're excited to support him and help him reach his immense potential," he emphasised.