Hermione Granger probably wouldn't have approved of staying out partying till 4 a.m. on her birthday, but her alter-ego Emma Watson didn't have a problem with it. Watson, star of the "Harry Potter" films, celebrated her 18th birthday with a sit down dinner for 70 close friends at London's Almada Club and a late night of partying.

Although none of her "Harry Potter" costars were at the dinner, Tom Felton, who plays Draco Malfoy, did show up around 10 p.m. when some of Watson's friends were invited for dancing. Who was in attendance, however, was Watson's new boyfriend Jay Barrymore, a 25-year-old banker she met through friends.

The birthday girl was wearing a black silk dress and according to People.com, seemed very thrilled with her new boyfriend.

Guests toasted the birthday girl with pink champagne followed by wines from Watson's father's own vineyard. Her mother made the birthday cake, a four-tiered cake that looked like a wedding cake.

Although Hogwarts would have never allowed such late partying, Watson and her friends stayed out till 4 a.m.