Dolly Parton has to be careful because her family has a history of depression.

The '9 to 5' hitmaker has revealed she is just as insecure as anybody else, and dismissed the idea she is ''happy all the time'', admitting to periods of feeling ''sad-hearted and melancholy''.

Speaking to the Daily Mirror newspaper, she said: ''Depression runs in my family on both sides and I have to be wary.

''It's usually brought on by something that's going on in the family and if there are problems sometimes it's a lot for one little person to carry ... People are always saying to me I'm happy all the time.

''But nobody is happy all the time. I am a tender-hearted person and I feel everything to the ninth degree. Every once in a while I just feel you know ... sad-hearted and melancholy. There are times when you just don't want to get up''

Although healthy in in relatively good spirits now, Dolly admitted 30 years ago when she was overweight following a partial hysterectomy, struggling with her business and upset she could never have children.

She admitted: ''It was a really bad time and it took two years just trying to get my physical weight and hormones in order. That was the first moment in my life that I slowed down.

''But sometimes God just has to smack you down. He was almost saying, 'Sit your pretty little ass down because we have to deal with some stuff.' ''