A little-known circular portrait of Charlotte Brontë will go on show at the Brontë Parsonage Museum in Haworth, West Yorkshire, next month.

It is one of only five of Charlotte and is thought to have been produced during her second stay in Brussels, when she complained in letters about having to sit for her friend Mary Dixon.

Alan Bentley, the museum's director, said yesterday that it was probably painted in 1843 when Charlotte was in her late 20s.

"It's different from the later portraits of her, which were the equivalent of today's publicity photographs," he said. "They certainly were not warts and all portraits."

The picture will be on show in the parsonage when it reopens after its January shutdown.

The portrait was bought at auction by the Brontë Society on its 111th birthday, just before Christmas, with the aid of grants from the Heritage Lottery Fund, the National Art Collection Fund and the Friends of National Libraries.

Mr Bentley said the picture had been sold by Arthur Brown, one of the Brontë family's servants, to William Law, a keen collector of Brontë material.

"The Law collection disappeared," he said. "It consisted mainly of letters and manuscripts and that part was catalogued. But we also know there were objects, which the Laws were not particularly interested in."

Law's descendants put it up for sale at Sotheby's.

The Brontë Society is thought to have paid about £25,000 for the portrait and other items, including a set of five miniature drawings by Charlotte, four landscapes, and a sketch of a woman in conversation with a parrot.

"They are very fine pieces of work," added Mr Bentley. "Charlotte is thought of primarily as a writer but she was also a good artist."