 Collett made his film debut as the younger version of Raymond Briggs in "Ethel & Ernest", a biographical film released in 2016.During 2017, Collett appeared in the short film "Honour" as 11-year-old boy Lee, and made a cameo appearance in the 2017 war film "Dunkirk", directed by Christopher Nolan.The following year, he appeared in "Dead in a Week or Your Money Back" as a younger version of the character William.