William Shakespeare wrote part of Double Falsehood, according to a University of Nottingham scholar. (Lefteris Pitarakis/Associated Press)

Nearly 400 years after the death of William Shakespeare, scholars are ready to add a new play to his canon.

It's called Double Falsehood or the Distressed Lovers and it's believed Shakespeare wrote the play in collaboration with another dramatist, John Fletcher, who took over as official playwright for the King's Men after the Bard.

Scholars have known about Double Falsehood for about 300 years, but recent analysis of the play, including its spelling and use of language, has led English literature professor Brean Hammond to the conclusion that much of it was written by Shakespeare.

"I think Shakespeare is probably responsible for very large parts of the first act, the second act and at least half of act three," said Hammond, a professor at the University of Nottingham. "From that point I think we see another hand taking over and it's Fletcher."

Hammond has worked since 2002 to determine if Double Falsehood has Shakespearean roots.

He believes the play is based on Cardenio, a Shakespearean work that is known to have existed but with no copies extant. Cardenio in turn was based on Don Quixote, which was released in English translation in 1612.

Recently, Arden Shakespeare, an authoritative publisher of the Bard's works, agreed with Hammond, though general editor and Shakespeare scholar Richard Proudfoot acknowledges there is no way to be sure.

"My position is one of fairly confident — but cautious — acceptance," he said. Arden has published a complete collection of Shakespeare's plays edited by Hammond that includes Double Falsehood.

It wouldn't be Shakespeare's first collaboration with Fletcher. He wrote two other plays with Fletcher towards the end of his career, Henry VIII and The Two Noble Kinsmen.

"At least half of the plays written in the period were written collaboratively," Hammond said.

In December 1727, theatre impresario Lewis Theobald backed a production of Double Falsehood in London's West End, saying in December 1727 he'd based his work on Shakespeare manuscripts.

The play initially got good reviews. But it was missing some Shakespeare hallmarks, like lengthy soliloquies. Then 18th century cultural experts weighed in and dismissed Theobald as a fraud.

"That was embarrassing for Theobald because he was trying to make his reputation as the great Shakespearean scholar of the day," Hammond said.

Hammond also faces naysayers. Prof. Tiffany Stern, a professor of early modern drama at Oxford University, said there is more of Theobald's stamp on the work than either Shakespeare or Fletcher.

She said Theobald could have proved his case by publishing the Shakespeare manuscripts he worked with, but he failed to do so.

The Swan Theatre, soon to reopen in Stratford-upon-Avon, U.K., is considering a production of Double Falsehood in its coming season.