But did she actually mingle with the royal couple? "I talked to William and Kate quite a bit. They're just a really awesome couple, lovely people, so I understand why people are fascinated by them. It was a really beautiful night - but then, I haven't been to many weddings."
The singer also spilled the beans on love and relationships, saying guys see her as marriage material.
"People seem to think I'm more wife material than girlfriend material. That's probably why I'm single!
"People might think I am but I'm not. I've been quite clever about what gets in the press but I've done some stupid things, some reckless things.
"A few too many drinks have caused a lot of things to happen."
Read the full feature in the February issue of Marie Claire, out today. Also available as a digital edition through Apple Newsstand.