Beyonce Miscarriage, Starlet Describes 'Saddest Thing I've Ever Been Through' in Revealing Documentary 'Life is But a Dream' [VIDEO]

In her upcoming HBO documentary "Life is but a Dream," popular songstress Beyonce gets very personal and even opens up about the heartbreaking miscarriage she experienced with husband Jay-Z about two years ago. The 31-year-old starlet has since given birth to adorable baby girl Blue Ivy, but that doesn't take away all the pain from what Beyonce considers the "saddest thing I've ever been through."

Jay-Z rapped about the tragic miscarriage in his 2012 hit "Glory" (featuring vocals by baby Blue Ivy):

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

Beyonce remained very quiet about the personal heartbreak... until now.

Us Weekly reports that the "Crazy in Love" star finally opens up about her first failed pregnancy in her upcoming documentary, "Life is but a Dream." Beyonce describes how the Hollywood power couple was excited to be expecting a baby together... they had even already begun picking out some names.

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

But such ecstatic happiness was brought to an abrupt end when Beyonce went for a standard check-up, and soon learned that her unborn child had no more heartbeat.

Like her hubby, Beyonce took to the studio to help push through the heartbreak:

"I went into the studio and wrote the saddest song I've ever written in my life ... And it was the best form of therapy for me, because it was the saddest thing I've ever been through."

The couple gave birth to baby Blue Ivy on January 7, 2012.

"Being pregnant was very much like falling in love. You are so open. You are so overjoyed," Beyonce goes on to explain. "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."

"Life is but a Dream" airs on HBO on Feb. 16.