London, May 12 : American pop and R and B singer Whitney Houston, who has not released an album in five years, is so worried she might forget her words on stage that she memorizes her lyrics backstage.

Houston, who fought and won a battle with drugs, became so nervous before her comeback gig at the Legends Ball, she had flunkies pin the lyrics to her famous songs to a wall.

The star even asked for an area backstage where she could memorize tracks.

"Whitney was really nervous before her set. She didn't make any diva demands and was polite to everyone," Daily Mirror quoted a backstage source as saying.

"She spent 45 minutes reading the lyrics, mouthing the words and holding her hands as if in prayer," the source added.

Celebrities including Mickey Rooney, Boyzone and Sugababes turned out in force to see Whitney's Evolution show in London.

The whole show went off without a glitch, and Houston never once forgot her words.