Thiam was born in Brussels. She wanted to be an actress from the age of four. She took a course in acting in New York at the
Lee Strasberg Theatre & Film Institute, staying only two months of a year-long course. Her mother is half-
Armenian and half-
Belgian. Her father is half-Senegalese, one-quarter English and one-quarter French; he was born in
Dakar. Her father is a percussionist and once toured with
Nina Simone. Her mother worked as an agent in Paris and Brussels for small fashion brands. She has one younger brother. Thiam modelled from the age of 4 and throughout her childhood and adolescence. She lived in the Paris neighbourhood,
Montmartre with her English grandmother, cousin, and family. Later, she was a student at the drama school, Cours Florent. == Career ==