Mary J. Blige's songwriting has been inspired by her own depression.

The 'Be Without You' hitmaker has revealed her song 'I Can See in Color' for 2009 movie 'Precious' - about an abused inner city teenager - took her back to her own struggles with depression.

She explained: "Precious was depressed, going through a lot of strife and it made me go back to my own life when I was going through my own depression. I wasn't able to see how beautiful the roses were or how beautiful the sunny day was. You can't see anything. You're walking through life in black and white.

"Everybody is not happy all the time. I'm a human being.

"Being a human being that is an artist, there probably is more dark than happy times. We're different. I have happiness and I'm content with who I am. But at the same time my life is full of ups and downs, I still get depressed."

The soul singer - who performed in front of US president Barack Obama and his family at his inaugural Celebration in 2009 - admitted she often thinks without her musical talent she would be "dead".

Mary, 39, added to the Chicago Tribune newspaper: "I sing and it makes me feel better. Absolutely that's my life in there. If God didn't give me a voice, I'd be dead. It's the only thing that saved me. I named my tour 'Music Saved My Life'. God used that instrument, my voice, to save my life."