The Sun newspaper (UK) reported on Thursday that Elton John will not be performing at the Brit Awards next month as he is on tour with Billy Joel and will be with him for an extra tour date. Looking at Elton's web site, he's performing in Philadelphia on the 19th February (the day before the awards in London) and on the 22nd. I also can't seem to find the news item that was on the Brit Awards web site a few days ago announcing the duet...
Jamiroquai played at the Sydney Entertainment Center in Australia today in 2002. This was an extra date added onto the end of their tour after the other gigs sold out so quickly.