John Hasler (born 21 April 1974) is an English actor who is best known for playing T-Shirt in the children's television series T-Bag from 1985 to 1992, and for voicing Thomas in the UK dub of the children's television series Thomas & Friends from 2015 to 2021. Hasler was the only cast member on T-Bag to remain with the show for its entire television run, starting as a young boy and leaving as a teenager.