A portrait by British artist Sir Herbert James Gunn (1893-1964) of his three children, entitled Design for a Portrait Group, will be sold at Bonhams as part of its 20th Century British Art sale today (June 30).
The picture was painted in 1929, two years after Sir Herbert's acrimonious divorce from his first wife Gwen, who had run off with Sir Arthur Whinney, one of her husband's sitters and a millionaire banker.
Gwen denied Sir Herbert access to his children and changed their names to Whinney.
According to his daughter from his second marriage, Chloe, Sir Herbert never mentioned his three children or first wife. The children, meanwhile, were led to believe that they had been abandoned by their father.
Sir Herbert happened upon his children by chance at London Zoo where he was preparing animal sketches for a mural.
The children, Pauline, Diana and Elizabeth, were with their nurse, who agreed to return with them for future sittings in Regent's Park. The nurse features in the picture alongside the children.
Sir Herbert kept the painting with him in his various studios until his death. It had preserved the memories of his children until they were reunited in adulthood.
The work will carry an estimate of £40,000-60,000 when it auctions in London.