The 38-year-old actor will play Robbie Ross, the best friend of Wilde in the film which marks the directorial debut of 'My Best Friend's Wedding' actor Rupert Everett, said The Hollywood Reporter.
Everett will write and star as Wilde in an ensemble cast that includes Colin Firth, Emily Watson and Tom Wilkinson.
Final casting is still underway for 'The Happy Prince', with principle photography set to start this October at Bavaria Film Studios in Munich and on locations in Italy, Belgium, France and the UK.