So, what should he play?
Fresh from her role as opera legend Maria Callas, the Oscar-winning actress is set to play a singer so bad that audiences flocked to hear her and laugh.
Meryl Streep has signed up to appear as Florence Foster Jenkins, the early 20th century American heiress, whose famously awful singing kept audiences in stitches at concerts and through her gramophone records.
Jenkins was ridiculed for her poor control of timing, pitch, and tone, and terrible pronunciation of foreign lyrics.
But the sheer entertainment value of her caterwauling packed out theatres around the United States, with the 'singer' firmly convinced of her own talent.
One critic wrote in the New York World-Telegram in 1944: "She was exceedingly happy in her work. It is a pity so few artists are. And the happiness was communicated as if by magic to her hearers..."
"People may say I can't sing," Foster Jenkins reportedly said, "but no one can ever say I didn't sing."
After a taxi crash in 1943, the singer discovered she could reach "a higher F than ever before", and sent the cab driver a box of expensive cigars in gratitude. She also often wore outrageous costumes that she designed herself, sometimes appearing in wings and tinsel.
Stephen Frears, director of The Queen and Philomena , is to make the movie which will also star Hugh Grant as the singer's partner and manager.