Lauren Conrad had no idea her fiance was going to propose.

The Hills star's boyfriend, William Tell, popped the question earlier this month, and while she was overjoyed, it came to her completely out of the blue. "I had no idea it was coming. I thought he would wait until he finished law school," she told the new issue of Cosmopolitan.

Lauren added rocker William even managed to pick the right ring all by himself: "He didn't even ask my friends, which was a bold move. He said, 'I know you, and I know what you like.' And I love it. It's perfect."

While Lauren, 27, is planning to wed the Something Corporate star, 33, as early as next autumn, she added the nuptials are only a small part of their overall relationship: "You have the rest of your life to be married. Enjoy falling in love. When girls get caught up in the timeline, it becomes more about the wedding than the marriage. You should be with someone with whom you could elope this weekend and be happy. If you're going to settle down, it should be with someone you can't stop thinking about. Especially if you're in your 20s."