[attach id=193782 size="medium"]The painting thought to be a hitherto unknown watercolour of all three Bronté sisters.[/attach]

A painting, believed to be a watercolour of the three Brontë sisters, is about to be auctioned.

And the auctioneer is hoping to score a hat-trick by selling the third item believed to be linked to the legendary literary pair.

The work is thought to be painted by 19th century English artist Sir Edwin Landseer and will be included in a two-day fine art and antiques sale this week at J.P. Humbert Auctioneers in Northamptonshire.

It follows the auction house’s sale of a small portrait believed to be of Emily Brontë recently for €5,632.

In December, J.P. Humbert’s sold another painting of the reclusive writer for €29,183.

The company said there was no estimate on the latest discovery as it was impossible to say how much it would fetch but he was hoping for a third sale of a Brontë-related artefact.

The piece of art is believed to be signed by Landseer, and matches known features of the sisters.

The sale of an unpublished manuscript by sibling Charlotte Brontë prompted a flurry of items relating to the literary sisters when it sold to a Paris museum for a record €600, at Sotheby’s in December.

The manuscript set new auction records for a manuscript by Charlotte Brontë and for a literary work by any of the sisters when it was bought by Paris museum La Musée des Lettres et Manuscrits.