Two-time Booker Prize winner Hilary Mantel said watching the stage version of her Thomas Cromwell novels is inspiring her to fini sh the third book in the best-selling trilogy.
Plays based on the first two books - Wolf Hall and Bring Up The Bodies - are performing to sell-out crowds in the west end of London after moving from Stratford.
The author, who is writing the final book which is reported to be called The Mirror and the Light , said: "I went home after the double show last Saturday, I sat down and wrote 2,000 words and that's the way it goes you know, a whole new scene, not directly related to what had happened on stage and yet something had triggered it".
Mantel, who has been a regular at the show since it moved, said she would soon start to dedicate more time to her writing.
She told the Press Association: "T hat will change over the summer. Once we're used to our London home, I won't be up sitting in the stalls every night, I will be going home to my desk and I will be pushing through that third book, I promise the readers.
"I t has to be right, it has to take the time it takes but I think it will be all the better for the work we're doing here".
A TV version of the books by the BBC has also been planned with Homeland star Damian Lewis playing Henry VIII and Mark Rylance as Cromwell - the man who rose from humble beginnings as a blacksmith's son to dominate the king's court before his fall from grace.
Other cast members include Claire Foy as Anne Boleyn, Joanne Whalley as Katherine of Aragon and Sherlock star Mark Gatiss as the King's secretary.