There’s a reference to Pretty Woman in The Princess’s Diaries.
In Pretty Woman, there’s a scene where Vivian (Julia Roberts) goes to dinner at an elegant restaurant. When she accidentally knocks over a snail, a waiter covers her sheer clumsiness by saying, “It happens all the time.” Mia (Anne Hathaway) in The Princess Diaries hears the exact phrase from the same waiter (Allan Kent) when she breaks a glass.