The signed pencil sketches on a single piece of paper titled Têtes (recto) and Nu debout (verso) were estimated at £40,000-60,000.
Drawing three telephone bidders, the lot was taken over double the top estimate before auctioneer and director of fine art at Cheffins Martin Millard knocked down his gavel.
The sketches from 1947 are stylistically typical of the great modern sculptor and came to auction from the family of the late antiques dealer Eila Grahame, who traded from a shop in Kensington Church Street for many years and who died in 2009.
Head of the paintings department at Cheffins Sarah Flynn said: “The price achieved today represents the rise in the popularity of Giacometti in recent years. Giacometti is one of the most revered and sought-after artists of the 20th century and we have seen interest from across the globe from museums and galleries as well as private collectors.
“Eila Grahame was a true icon in the antique collecting world and we knew that anything from her collection would be highly desirable, including this important previously unrecorded work.”
The proceeds of the Eila Grahame estate will be divided equally between the Art Fund and the Church of St Mary of the Assumption, Ufford.