Christie’s auctioneers, who are selling the necklace, are characteristically discreet about potential purchasers but they have disclosed that the necklace once graced the neck of a teenage Spanish dancer called Anita Delgado from Malaga who captured the heart of Maharaja Jagatjit Singh.

The couple were wed in 1907, one year after Anita caught the Maharaja’s eye during his visit to Spain in 1906 to attend the marriage of King Alfonso XIII of Spain and Princess Victoria Eugenia of Battenberg. Anita became Jagatjit Singh’s fifth Maharani and was known as Prem Kaur until her divorce in 1925.

The centrepiece of the necklace given to her for her 19th birthday is a crescent-shaped emerald surrounded by diamonds that was previously used as a decoration for Jagatjit Singh’s favourite elephant.

Originally set as a brooch, its sale price is estimated at upto £100,000. Another early 20th century diamond and ruby pendent necklace, valued at between £40,000-50,000, is designed as a stylized basket of flowers, with a later Art Deco diamond-link neck-chain with ruby spacers, epitomizing the dynamic line synonymous with this popular period.

More items up for sale from the collection include a pair of geometric, sapphire and diamond clips, valued at £10,000-£15,000, a ruby and diamond clip brooch from 1925, valued at between £5,000-8,000, two pairs of diamond ear pendants and an emerald bracelet band valued at between £20,000 and £30,000.

The Maharani had one son, Ajit Singh, who died in 1982. Her own marriage to the Maharaja ended in divorce. According to the author of a recently published book about the Kapurthala couple, their marriage ended in divorce after the Maharani fell in love with one of the Maharaja’s sons from a previous marriage. This claim has been denied by the Maharaja’s descendants who have been trying to block the making of a film about Delgado starring Penelope Cruz.

Christie’s estimates their total value at more than £200,000. Said Christie’s international director of Asian art Amin Jaffer: “These jewels are a symbol of cross-cultural love and taste, bringing together Indian princely patronage with the finest European craftsmanship and design.”