Singer Jordin Sparks cheered up sick children in a Memphis, Tennessee hospital last week by staging a surprise show.

The former American Idol winner visited St. Jude Children's Research Hospital on Friday and performed a 90-minute set for patients and their families.

Sparks sang a number of her own hits and even previewed a track from her upcoming movie musical Sparkle, before taking time to visit youngsters on the wards.

In a post on her Twitter.com page, she writes, "I had a great time performing 4 (for) St Jude patients & their families... What an inspiring group of kids!"