Olivia Newton-John as Judge on 'American Idol'

Among the many celebrities that join the list of long-time judges on the talent competition 'American Idol' was also the 'Grease' star and best-selling singer, Olivia Newton John, who just turned 58 on Tuesday.

Olivia joined Simon Cowell, Randy Jackson, Paula Abdul and the show host Ryan Seacrest to decide which of the thousands of contestants will make the cut and star in the next season of the successful show. After receiving a birthday cake from the other judges and listening intently to every aspiring singer that came to the auditions, Olivia left the scene very impressed.

'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.', the singer said after the audition ended. She also told the Associated Press that she had the time of her life, save the moment when she had to tell the young aspirants that they were not fit to enter the final rounds of the contest.

The star, who made her debut on another talent competition called 'Sing, Sing, Sing', said that she can relate to all of those who were rejected, just because she had been there too. 'I always remember what it was like for me and what it would have been like to be told no. So I do feel for them. It's hard. But sometimes it's probably kind for them, because they won't pursue something they don't really have the talent for', Newton-John explained, trying to look on the more positive side of things.

The sixth season of 'American Idol' premieres in January, on FOX.