Championed by John Singer Sargent who bought a portrait from him for 1000 francs when Helleu was just 18, the French artist went on to produce numerous works in oil, pastel and over 2000 drypoint etchings.
Sargent's influence permeates this portrait etching of Nancy Beatrice Borwick, Lady Croft (1884-1949), which is going under the hammer at Sworders' Country House sale in Stansted Mountfitchet on December 8 guided at £1500-2500.
Lady Croft was the wife of Brigadier General Henry Page Croft, later the 1st Baron Croft, who served as Under Secretary of State for War under Winston Churchill from 1940-45. She probably sat for this portrait around the time of her marriage in 1907.
The 15 x 11in (39 x 29.3cm) signed work has been consigned from the estate of Lady Croft's youngest daughter, who died earlier this year. The family lived at Fanhams Hall near Ware.
Also on offer in Sworders' December 8 sale are a pair of fresh to the market sandstone figures dating from late 12th/early 13th century - the zenith of the Angkor period of the Khmer Empire, which flourished from the 9th to 15th centuries and left, as its greatest legacy, the Angkor Wat temple complex, which dates to the same period as this pair.
The first is a figure of a dancing Apsara, in the Bayon style - named after a famous Angkor temple - standing 16in (41cm) high and estimated at £8000-12,000.
The other is a 2ft 8½in (83cm) torso of a Dvarapala, a guardian of the gate, also in the Bayon style which carries hopes of £10,000-15,000.
Both are consigned from a private UK collection, having been purchased from the Vichai Gallery in Bangkok in 1965 and shipped to London in 1969.