[attach id=246651 size="medium"]Photo: National Portrait Gallery/PA[/attach]

Downton Abbey actress Dame Maggie Smith is swapping high society for high art after a new portrait of the star was unveiled.

The painting of the Oscar-winning actress, who plays the Dowager Countess of Grantham in the hit period drama, was commissioned by the National Portrait Gallery.

The work, which measures six foot by three foot, shows the actress in artist James Lloyd’s studio in south London.

Lloyd, who started the painting in 2011, had to fit around Dame Maggie’s schedule and her changing appearance which saw her dye her hair peroxide blonde at one point for a role in the film Quartet.

He said: “I was delighted to be asked by the National Portrait Gallery to paint Dame Maggie Smith, not only because this was an opportunity to have a third painting in the gallery’s collection, but also for the honour of trying to portray such a luminary of stage and film.

“I learnt that Dame Maggie had been reluctant to have her portrait painted in the past, and at my first meeting with her, her opening words were, ‘Poor you’.

“This was quite the opposite from my own feelings, and everyone to whom I mentioned the commission was extremely envious – I lost count of the number of people who offered to make tea during the sittings!”

Dame Maggie won her first Oscar in 1969 for her performance in The Prime of Miss Jean Brodie, before winning again in 1978.

She is also known to millions for her appearances in the Harry Potter films.

The portrait goes on show in the central London gallery today.