"I Still Believe", the romantic movie based on Jeremy Camp and his late first wife Melissa, opens in US cinemas this Friday, but the worship artist admits it's brought back lots of painful memories.

The biopic takes its name from the song Camp wrote as a result of losing Melissa to cancer in 2001, less than a year after they were married. 

He told The Christian Post that he feels "blown away" having his story told in a movie.  But it's also been challenging to re-visit the pain and grief over Melissa's death. 

"A lot of people say, 'Wow, a movie on your life, isn't that exciting?' Absolutely, I'm blown away that God allowed me to do this but it's hard — watching the film and being a part of it," he said. 

"It's the hardest part of my life, where I actually experienced some very difficult grief and pain. So I think the reality is, so every time I watch it, I do break down because I'm reminded of that pain." 

Camp is portrayed by Riverdale star KJ Apa in the movie, while Tomorrowland actress Britt Robertson takes the role of Melissa. Rounding out the cast are country singer Shania Twain as his mother, and Forest Gump star Gary Sinise as his father. 

The "Walk by Faith" singer was present on set during filming with his second wife of 16 years, Adrienne.  He spoke of the support he received from her when some of the more emotional scenes were being shot. 

"One beautiful thing that happened during the filming, we were filming and it was a really difficult scene and I had to walk away because I broke down," Camp said.

"I just started weeping, my wife followed me and I just cried on her shoulder for a while. I got back into the filming and I'm sitting there, and I'm watching my family and they're in front of me. It's my wife, my three kids. I'm like, 'Wow, God, look what you've done.'

"I have my family now and I'm able to go and minister around the world, your goodness and your faithfulness." 

He went on to say that he hopes the movie will "open more doors to minister the Gospel" and help people struggling with pain. 

"Of course, you want Christians to be encouraged with the film and I want believers to go watch it," he said.

"But honestly, I want the people who don't know Jesus to watch this because I want them to understand that the only reason why I was able to get through my trial and we were able to get through that trial because He was by our side every moment. 

"Everybody in this generation really is searching for hope. There are so many things and battles and divisions and all this and people are grasping for hope in some way. And for us to present this [movie] as a 'this is difficult, this is the trial, this is pain and hurt and loss, but there's hope,' I think that's so huge and pointing that hope to Jesus."