Sarah Brightman didn't play jelleroum, she played jemima in the original cast of cats, Susan jane tunner played Jelleroum in the original cast of cats, Sarah Brightman just recorded this song for this album.
She had a very long history with Andrew Lloyd Webber (creator of cats, Phantom of the opera, jesus Christ superstar and more). They even got married at one point but went through a divorce in the 90's although it seems that they're on very good terms nowadays
