She poses as a radio seller, working with secret agent Rene Mathis, and later as Bond's companion to infiltrate the casino in Royale-Les-Eaux, where Le Chiffre frequently gambles. She is lent to Bond, much to his irritation, to assist him in his mission to bankrupt Le Chiffre, the paymaster of a SMERSH-controlled trade union. Vesper works at MI6 headquarters as a personal assistant to the Head of Section S. In 1993, journalist Donald McCormick claimed that Fleming based Vesper on Polish agent Krystyna Skarbek, who was working for Special Operations Executive when he knew her. The actual name for the drink (as well as its complete recipe) was mentioned on screen for the first time in the 2006 film adaptation of Casino Royale.

The ' Vesper' became popular after the novel's publication. In the novel, the character explains that she was born 'on a very stormy evening', and that her parents named her 'Vesper', Latin for 'evening' and Bond then gives her name to a cocktail he has recently invented. She was portrayed by Ursula Andress in the 1967 James Bond parody, which is only slightly based on the novel, and by Eva Green in the 2006 film adaptation.

Vesper Lynd is a fictional character featured in Ian Fleming's 1953 James Bond novel Casino Royale.