Celebrities at weddings – is it a good idea?

I've been wondering what it must be like having a celebrity at your wedding.
Seth Green said his guests were left speechless when George Lucas turned up at his wedding venue.
The actor has worked with the Star Wars director over the past decade and according to WENN, the pair have become friends.
However, although Green described Lucas as "a normal dude", he explained his family and friends were shocked to have him in the wedding photography.
"Everyone was like, 'Oh my gosh, I don't know what to say to him.' And he's hanging out, like, 'I wish somebody would say hi to me'," he said.
There seems to have been quite a few famous faces making the news for attending weddings recently.
Pixie Lott was pictured in a cute ballerina-style bridesmaid dress, while Sir Cliff Richard drove his niece to her wedding ceremony in a Bentley.
Plus, we all know about Katie Price's recent nuptials and the celebs such as Danielle Lloyd, Melina Messenger and Michelle Heaton who turned up to that event.
This got me wondering what it must be like having a celebrity at your wedding. Obviously if it's a good friend or relative you'd want them there, but would they overshadow the main event? Especially if the press got wind of it and ruined your big day by gathering outside in the hope of getting a few snaps.
Also, there might be some people who would be tempted to invite a famous face even if they don’t know them that well and I think this ruins the whole point of the special day.
Would you invite a celeb to your wedding if you knew one?