The Dutch international has agreed to join the Reds from Bayern Munich (subject to registration), becoming the club's third signing of the 2024 summer transfer window.
And now it has been revealed that the 25-year-old, who celebrated his birthday on Monday (12 August) will don the no.4 jersey when he takes to the field as a United player.
De Ligt has worn the very same number during most of his senior club career thus far, although he was no.36 during his first season at Ajax.
He famously rose to prominence as a youngster in Amsterdam, starting the 2017 UEFA Europa League final as a 17-year-old, where the Eredivisie club were beaten 2-0 by Jose Mourinho's Reds.