Beyonce has spoken for the first time about losing her first baby two years ago, revealing she had already picked out names when doctors told her the devastating news.

The singer gave birth to a daughter named Blue Ivy last year, and just days afterwards, her husband Jay-Z released a song which suggested they had endured a previous tragedy.

Beyonce has now confirmed she conceived for the first time two years ago, and was grief-stricken when she lost the child.

Speaking in her new documentary "Life Is But a Dream", she says, "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. I picked out names. I envisioned what my child would look like... I was feeling very maternal. I flew back to New York to get my check up - and no heartbeat. Literally the week before, I went to the doctor, everything was fine, but there was no heartbeat."

Beyonce admits she dealt with the tragedy by pouring her emotions out in her music, "I went into the studio and wrote the saddest song I've ever written in my life. And it was actually the first song I wrote for my (last) album. And it was the best form of therapy for me, because it was the saddest thing I've ever been through."

However, the "Crazy In Love" hitmaker insists experiencing such a sad loss made her even more grateful when she eventually gave birth to baby Blue.

She adds, "Being pregnant (with Blue Ivy) was 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."