The Girls Aloud singer will play Jenny beginning in January.
The 'Harry Potter' star praised the writer for 'bringing joy to so many different generations and walks of life.'
Felton, who famously played Draco Malfoy, and Mandip Gill have been announced as stars in the transfer of 2:22 - A Ghost Story to the Criterion Theatre in the West End.
Fans were worried after pictures emerged of Tom Felton being stretchered away from a US golf course.
The actor says she was a guiding light in his career and personal life.
The 32-year-old Harry Potter shared a sweet picture of his baby girl, named Wednesday.
The 29-year-old actress has declared herself 'self-partnered'.
Harry Potter stars Tom Felton and Matthew Lewis had one of their occasional reunions yesterday, but Felton clearly had an ulterior motive for meeting up with his former cast-mate.