Beyonce Knowles often wonders why God gave her the life she has.

The singer-and-actress - who is deeply religious - is very grateful that her talent has given her a lifestyle most people could only dream of and while she sometimes she finds it "overwhelming" she knows God chose her for a reason.

She said: "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."

Beyonce was opening up in a new documentary, 'I Am World Tour', and says she decided to let a camera crew into her life because she sometimes feels lonely while on the road.

She said: "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."

Beyonce - who is married to hip-hop superstar Jay-Z - also revealed she is not quite ready to be a mother as she still has things she wants to achieve.

Talking about babies, she said: "Nothing now but there will be one day. One of the reasons I haven't had a child yet is because there are certain things I want to do before I focus on being a mother. I'm not there yet but I'm close."