Leo Tang
From Tardis Wiki, the free Doctor Who reference
Leo Tang (born 2008[1]) played the fourth incarnation of the Timeless Child in the Doctor Who television story The Timeless Children.[1] As of 2021, he is the most recently born actor to be on the programme. By extension, this would also make him the youngest ever actor to portray the Doctor in any capacity.
Footnotes
Gets bullied because of this role