The titular 'Prince Caspian' is played by Ben Barnes in the second Chronicles of Narnia movie, and this is the costume he wears in the opening scenes in his dramatic escape from his evil uncle, Lord Miraz's, castle into the surrounding woodland.
Original Prince Caspian costume worn by Ben Barnes
This original costume, designed by Isis Mussenden, was photographed on display within the Journey into Narnia: Prince Caspian walk-through attraction at Disney's Hollywood Studios in Orlando on September 22, 2010.
The Chronicles of Narnia: Prince Caspian movie poster
Actual Lord Miraz and Prince Caspian costumes on display
Dress like Prince Caspian and buy the Halloween costume: Narnia Prince Caspian Costume - Disney Child Costume deluxe