Watch KJ Apa Propose to Britt Robertson in an Exclusive Clip From 'I Still Believe'

The faith-based romance tells a real-life story of love, loss and music.

KJ Apa is swapping the amateur vigilantism and jingle jangle of Riverdale for a more pious love story in his new movie, I Still Believe -- and ET can exclusively debut a clip of his romantic proposal to Britt Robertson.

The duo -- who starred in 2017's A Dog's Purpose and were previously linked as more than just co-stars -- play Christian singer-songwriter Jeremy Camp and his wife, Melissa Henning-Camp, in the latest faith-based romance from the Erwin Brothers. Like the directors' last film, I Can Only Imagine, this tells a real-life story of love, loss and music. (The film's namesake is the 2002 song, "I Still Believe.")

"I want you to know that whatever this is and wherever it takes us, that I'm with you. Every step, every moment, I'm with you. I'm in. I'm so in," Apa's Jeremy says in the clip. (Watch it above.) "And I figure if we're going to get married, we have a lot to talk about..."

"Married?!" Melissa replies in disbelief.

I Still Believe opens in theaters March 13. (If you want to meet Apa, Lionsgate is offering the chance to do just that via their #IStillBelieveCover contest. You can find all the details here.)

Image via Lionsgate