The movie I Can Only Imagine goes behind the scenes to tell how Bart Millard of the Christian band, MercyMe, wrote the chart-topping song.

“My dad was incredibly abusive my whole childhood until he was diagnosed with cancer when I was in high school, and he fell desperately and passionately in love with Jesus – to the point that when he passed away, he was my hero … the godliest man I ever knew,” Millard shared.

The words to the song were first uttered through the lips of his grandmother at his father’s funeral.

“And the song was written after leaving his gravesite,” the now-Christian music star expressed. “My grandmother said I can only imagine what your dad is seeing now.”

Millard told OneNewsNow that he held on to those words for a few years and wrote that phrase down on everything he could get is hands on.  This led up to what seemed to be MercyMe’s most providential song.

“MercyMe was now a band and we needed one more song for an independent record, and I tried to find a blank page to write on and every single page had ‘imagine’ or ‘I can only imagine’ written on it ,” Millard recalled. “So, I kind of got the memo and wrote something that had been on my heart for a couple of years in about 10 minutes – and it changed everything.”

The movie hits theaters nationwide on March 16. Millard also has a memoir that is releasing alongside the film.