Diana Adores the Puzzled Duke by Hanna Hamilton

Robert, the young and handsome Earl of Donnelly, has a great passion for writing novels but as part of the nobility, it is socially impossible for him to openly publish fiction in his own name.
After much searching, he finds the young Diana Browning, a charming and well-established romance writer, who agrees to publish the book under her name.
As Diana and Robert begin to work together, they find they are becoming increasingly attracted to each other. But, Diana is engaged and unavailable.
However, circumstances contrive to bring many surprises, and nothing comes out as anyone quite expected.