Before Lili Reinhart became Olive Smith and Rachel Marsh became Anh Pham in The Love Hypothesis, both actresses had already read Ali Hazelwood's bestselling novel.
Lili Reinhart already knew Olive
Reinhart told PEOPLE that she had read Hazelwood's book before joining the movie. She said the opportunity to play Olive felt meaningful even though her own background is very different from the character's academic life.
Olive is a Stanford Ph.D. candidate working in science, while Reinhart has said she did not attend college and did not identify with Olive's scientific expertise. What connected her to the role was the character's emotional journey and the opportunity to portray a woman in STEM.
Rachel Marsh read the novel too
Marsh, who plays Olive's best friend Anh, also read the novel before accepting the part. PEOPLE reported that the book changed her view of the romance genre and that she became especially interested in the friendship between Olive and Anh.
Why Olive and Anh matter to the movie
The friendship is more than a side plot. Olive's fake-dating plan begins because she wants Anh to believe she has moved on from Jeremy, the man they both have feelings for. That makes Anh one of the reasons the movie's central romantic deception starts at all.
Who plays Adam Carlsen?
Tom Bateman plays Dr. Adam Carlsen, the intimidating professor who becomes Olive's fake boyfriend. The cast also includes Jaboukie Young-White, Nicholas Duvernay and Arty Froushan.
Is the movie faithful to Ali Hazelwood's book?
The adaptation keeps the novel's central fake-dating setup, characters and academic setting. As with most feature adaptations, some material from the book has been condensed or rearranged to fit a movie-length story.
Hazelwood's reported support for the adaptation also gives book readers another piece of context when they compare the movie with the 2021 novel.
Where to watch The Love Hypothesis
The Love Hypothesis streams globally on Prime Video September 23, 2026. It is based on Hazelwood's New York Times bestselling romance novel.
Sources
Author: Shivam Das
