Beyonce opens up for the first time about the miscarriage she suffered two years ago in "Life Is But A Dream," her self-directed documentary that will air on HBO in February.

According to USA Today who saw the film, the "Halo" singer said she realized that something was wrong when she heard a heart beat one week and the next week she didn't.

"About two years ago, I was pregnant for the first time," the Grammy winner said. "And I heard the heartbeat, which was the most beautiful music I ever heard in my life. I picked out names.  envisioned what my child would look like . . . I was feeling very maternal."

Later, the Houston native realized something was not right with the pregnancy.

"I flew back to New York to get my check up -- and no heartbeat," she said. "Literally the week before I went to the doctor, everything was fine, but there was no heartbeart."

Beyonce said after the loss of her unborn child, she went into a recoding studio and wrote "the saddest song I've ever written in my life."

"And it was actually the first song I wrote for my album," she added, "And it was the best form of therapy for me, because it was the saddest thing I've ever been through."

She then described the experience of being pregnant with Blue Ivy as being "very much like falling in love."

"You are so open. You are so overjoyed. There's no words that can express having a baby growing inside of you, so of course you want to scream it out and tell everyone."

Beyonce's fans did not learn that she suffered a miscarriage until after she gave birth to Blue Ivy on Jan. 7. Her husband, Jay-Z, mentioned it in "Glory," the rap song he recorded and released within days of Blue's birth.

"Last time the miscarriage was so tragic/We was afraid you'd disappear/But nah baby you magic," he rapped.

"Life Is But A Dream" will air on HBO on Feb. 16.

Beyonce will headline the Super Bowl halftime show on Sunday, Feb. 3 at the Mercedes Benz Superdome in New Orleans less than two weeks before the documentary will air.