Kate Middleton's Siblings Didn't Know She Was Engaged

"Extra" caught up with famed journalist Martin Bashir to find out his thoughts on Prince William and Kate Middleton's engagement.

prince william and kate middleton

Bashir -- who knew Prince William's mother, the late Princess Diana, very well -- said that the Prince and his fiancee plan to keep their life as private as possible.

"Kate's brother and sister were told that she got engaged just three hours before it was announced publicly," Bashir said, despite the fact the pair has reportedly been engaged since October. "They told virtually nobody."

Gallery: Prince William and Kate Middleton Photos!

Bashir believed William's insistence on privacy comes from Princess Diana's relationship with the media. "I think in part that's because of Prince William's experience of his mother's life. She was in the newspapers every single day... much of her life was played out like a soap opera

The journalist added, "If there is one thing that Prince William doesn't want, is any of that. In a way, I think he's almost tested the Middleton family. They've been together for something like nine years. He's been to the family home. Has that ever been discussed in the press? No! Has it ever been leaked to a journalist? No!"

Bashir also thinks this union will last. "I think this is much more about romance than anything else. William met this young lady at University. He didn't meet her at a polo match or on the grounds at Buckingham Palace. He met her at University. There's a certain meritocracy about this relationship. And I think that a more modern marriage that a traditional one."

For more of Bashir's interview tune-in to "Extra" Friday.