Rocker Sheryl Crow was stunned to discover the horse which helped her through her breast cancer battle a year ago (06) is pregnant, after failing to realize how fat she was getting.

The Soak Up The Sun singer rode Sally, the horse she houses at her ranch in Nashville, Tennessee in Los Angeles to cheer herself up during lows in her treatment, and was perplexed when the normally dependable beast started tripping on rides recently.

She says, "The woman that was boarding her thought she was just so fat and I kept thinking, 'She doesn't look that fat to me.' And she kept tripping, and this is a very dependable horse.

"I kept having vets come out and they all kept saying, 'She looks really fat.' And I kept saying, 'She can't be pregnant because there’s not been any stallion around.' "It turns out that I didn't realize that horses have an 11 month gestation period, so she was pregnant.

"The way I found out was the baby kicked me, kicked my leg.