Youngest actor to receive star billing

Youngest actor to receive star billing
Who
Leroy Overacker
Where
United States
When
1933
Leroy Overacker (USA) (b. 12 May 1932), known on screen as 'Baby Leroy', was chosen at the age of six months to play opposite Maurice Chevalier in A Bedtime Story (USA 1933). His grandfather had to sign the contract, because not only was the star under age, but so was his 16-year-old mother.

Appearing in nine films betwee 1933 - 1936, he retired at the age of four.