The Belgian royal court recently announced that Their Royal Highnesses Crown Prince Philippe and Crown Princess Mathilde of Belgium will attend the upcoming British royal wedding on April 29, 2011.
So, here is the list of royals who have confirmed their attendance thus far:
- H.S.H. Prince Albert II of Monaco and his fiancée, Charlene Wittstock
- Her Majesty Queen Margrethe and H.R.H. Prince Henrik of Denmark
- Their Majesties King Harald and Queen Sonja of Norway
- Ex-King Constantine and Ex-Queen Anne-Marie of Greece
- Their Royal Highnesses Crown Prince Willem-Alexander and Crown Princess Maxima of the Netherlands
- Sheikha Mozah of Qatar
- Their Royal Highnesses Crown Prince Alexander and Crown Princess Catherine of Serbia
- Their Royal Highnesses Crown Princess Victoria and Prince Daniel of Sweden
Source: SkyNet.be Photo courtesy of: Zimbio.com by Bauer Griffin
royalcorrespondent.com 
I feel sorry for them, but I guess they are rather forced to go.