The 29-year-old British actor plays a young version of the Lord of the Rings author in a preview of the new movie.
The trailer shows Tolkien (Hoult) tell a story to his wife and muse, Edith Bratt (Lily Collins). The author wrote The Hobbit and The Lord of the Rings following his experiences in World War I.
"It's a story about journeys -- the journeys we take to prove ourselves," he says. "About what it means to love and be loved. Have courage. It's about fellowship."
Tolkien is directed by Finnish director Dome Karukoski and co-stars Colm Meaney, Tom Glynn-Carney and Anthony Boyle. The film explores Tolkien's early life as an orphan and how WWI influenced his vision of Middle-earth.
Collins confirmed in January that Tolkien will open in theaters May 10.
"Surprise! Tolkien is coming out in 4 months!" she tweeted. "So excited to share this beautiful story about such a revered and epic storyteller. Welcome to the Fellowship."
Tolkien was best known for The Hobbit, which debuted in 1937, and the Lord of the Rings trilogy of books, published in the 1950s. The author died at age 81 in September 1973.