I heard an interview with him on the radio several months ago, as he was preparing to do a gig at Ronnie Scott's Jazz Club in London.
He basically said that he made enough money from his Stock Aitken and Waterman days to live a comfortably life, and no longer chase stardom, and was now doing the above performance to play music that he really cared about.
According to his website (which I just found via Google);
http://www.rickastley.co.uk/ He is about to tour and has a new record deal.