LATEST: Sir Paul McCartney has dismissed reports he is dating SABRINA GUINNESS - insisting she is just an "old friend". The former beatle was spotted with the 52-year-old - a former girlfriend of SIR Mick Jagger and British royal Prince Charles - in London on Wednesday (21MAR07) evening. But MCCartney has denied claims he is romantically linked to the Guinness drinks empire heiress since splitting from Heather Mills last year (06). He says, "It's nothing more than friendship. I realise everyone wants to see me with a new bird right now, and that's really flattering. "I have had a terrible day at the office and as you probably know, I'm going through a pretty difficult divorce right now too. "But I have known this lady for quite a while and we just enjoy each other's company. When we get together, we speak about stuff like the environment and (US politician-turned-activist) Al Gore." A spokesperson for the star also denied the allegations of a romance, saying, "There is no relationship (between the pair) beyond friendship."