Actor Nat Wolff and actress Laura Dern are joining The Fault in Our Stars movie based on the book by John Green.

Wolff will play Isaac, Augustus’ best friend. The actor had hinted at his involvement with the film several weeks ago. He is no stranger to working with director Josh Boone; he starred in his first movie Stuck in Love which hit theaters last month. Wolff had originally auditioned to play Gus.

Dern will play Hazel’s mother. The actress most recently starred in HBO’s Enlightened, which we were sorry to see get canceled after season 2.

The Fault in Our Stars movie is currently in pre-production and will begin shooting in late August. Boone is already preparing in Pittsburgh where the majority of the film will be shot before heading to Amsterdam for scenes for later portions of the book.

Shailene Woodley will play Hazel and Ansel Elgort will play Gus. At Comic-Con, Elgort said that he and Woodley will be visiting cancer hospitals to speak to those who are suffering the same conditions Hazel and Gus do in the book.

The Fault in Our Stars will open in theaters in 2015. It will be scored by members of Bright Eyes who also composed Stuck in Love for Boone.