Justin Baldoni Reveals How Taylor Swift's Song in 'It Ends With Us' Came to Be (Exclusive)

Justin Baldoni spoke with ET from the premiere of 'The Garfield Movie.'

Justin Baldoni is giving his It Ends With Us co-star Blake Lively all the credit for getting Taylor Swift to lend her voice to the newly-released trailer for their film. 

Talking with ET's Kevin Frazier from Sunday's premiere of The Garfield Movie -- which hits theaters on May 24 -- the 40-year-old Jane the Virgin actor shared that to get Swift's "My Tears Ricochet" as the background music for the first trailer, Lively, 36, cashed in on her longtime friendship with the 34-year-old crooner.

"That's all Blake," Baldoni told ET. "I have no idea [how she did it] but Blake knows everybody... her and Taylor are very good friends. I'm so happy that they agreed to have a song in the trailer, it's so perfect for the movie."

In the trailer, Baldoni and Lively -- who star as Ryle Kincaid and Lily Bloom, respectively -- experience the early stages of love and romance before things take a sudden and drastic turn. 

Justin Baldoni and Blake Lively in 'It Ends With Us' - Robert Kamau/GC Images

The film follows Lily, who finds herself in an abusive relationship and desperately searching for a way out, when a former friend -- played by Brandon Sklenar -- comes back into her life at the right time. The movie, which also stars Jenny Slate and Hasan Minhaj, is based on the bestselling novel of the same name by Colleen Hoover

Baldoni told ET over the weekend that while fan reactions to photos from the set back in May 2023 -- which showed Lively with red hair and funky costumes -- were mixed, he is excited by the overall sentiment in the days since the trailer dropped. 

"I'm just happy that the reaction has been so positive. I know fans have been waiting a long time for this and it's a very special book for a lot of reasons -- to a lot of women, especially -- and our mission is just to do right by them," Baldoni shared.

Watch the trailer for It Ends With Us in the player below: 

Just last week, the actor chatted with ET alongside Hoover, 44, and said he isn't worried about the critiques. Instead, the Jane the Virgin alum has one bit of advice for worried fans: "Just go see the movie."

"I understand when you love something so much, you know, social media is amazing in [the] way it gives fans a voice," he said. "And if it were not for the fans, we would not be making this movie. So let them talk. And I don't worry about that too much."

As for the pictures from the set that some fans critiqued, Baldoni said that the photos only show "one moment from one part of Lily's life" and don't provide full context of what the film will actually look like.

Hoover also responded to fan concerns over the film's decision to age the characters up. The book follows Lily and Ryle in their 20s, while Baldoni and Lively were 39 and 35 while filming. 

"I started writing this book over 10 years ago when I was in my early 30s [and] when new adults, the genre and the younger ages, were really popular with publishers at that time. But I think it hits harder and closer to home with them aged up," she told ET, adding that she's "really glad" with the change.  

It Ends With Us hits theaters on Aug. 9. 

RELATED CONTENT: