Olivia Newton-John has sympathised with American Idol contestants as she stepped in to guest judge an episode of the TV talent contest yesterday (26SEP06). The GREASE star, who launched her own singing career after appearing on Australian show SING, SING, SING as a teenager, admits she was impressed by some of the talent on display at the auditions. She says, "Some of them are very young and they're green but you can see their potential. They have a different voice or a different way of presenting themselves." She also spoke of her despair at having to reject some hopefuls: "I always remember what it was like for me and what it would have felt like to be told no. So I do feel for them. It's hard. "But sometimes it's probably kinder for them, because they won't pursue something they don't really have the talent for." The pop star joined regular show judges Simon Cowell, Randy Jackson and Paula Abdul for the programme, who presented the singer with a birthday cake for her efforts. She turned 58 yesterday.