10. And there were other celebs, too!
Like Rose's Downton Abbey costar Sophie McShera.
Also in attendance was musician Marcus Mumford, along with his bandmates from Mumford & Sons. (Fun fact: Marcus also attended Prince Harry and Meghan Markle's wedding with wife Carey Mulligan!)
Malin Akerman joined in for the celebration with her fiancé and shared some of the only behind-the-scenes photos on Instagram from the big day.
Rose's Honeymoon costar, Penny Dreadful actor Harry Treadaway, brought actress Holliday Grainger as his date.
