AceShowbiz - Singing superstar Beyonce Knowles showed the lonelier side of fame while filming her new documentary, breaking down in tears as she asked: "Why did God give me this life?" The former Destiny's Child star turned the camera on herself during her last global trek, the I Am... Tour, to document her time on the road.

In the footage, the emotional pop star can be seen tearing up as she admits she sometimes feels "overwhelmed" by her success. Speaking in I Am... World Tour, she says, "Why did God give me this life?... Sometimes it's overwhelming. Why did God give me my talent, my gift, my family? But I know you're not supposed to question God. Only God knows. And I don't take it for granted."

The "Crazy in Love" hitmaker, who produced and directed the film, debated whether to include the emotional scenes but decided she wanted to show fans the real Beyonce. She adds, "I wanted the fans to be able to see what I see. It's a lot of things I reveal about myself that I could never give to a director."

"There was one moment I was in China and I was in this huge suite and I looked out the window and there were just thousands of people walking and I couldn't believe my life. I guess I was a bit lonely and I wanted to talk to someone so I opened up my computer and I just talked."