Eaton was born on 12 January 1937 in Edgware General Hospital, Middlesex, and brought up in the suburb of Kingsbury.

Throughout her career, Eaton appeared with many of the top British male comedy stars of the period, including Jimmy Edwards, Max Bygraves, Bob Monkhouse, and Arthur Askey.

Eaton's female co-stars included Peggy Mount, Thora Hird, and Dora Bryan among others.

Eaton achieved the most recognition for her performance as Jill Masterson in the 1964 James Bond film Goldfinger (1964).

(1964) and Around the World Under the Sea (1966), a Harry Alan Towers version of the Agatha Christie mystery Ten Little Indians (1965) co-starring Hugh O'Brian and a Bob Hope comedy, Eight on the Lam (1967), plus the title role of Sax Rohmer's Sumuru in Towers' The Million Eyes of Sumuru (1967) and The Girl from Rio (1969).

In a 2014 interview, she explained, "After I finished The Million Eyes of Sumuru and was coming home in the plane was when I made the decision to quit.

She repeated this statement in an interview with the journalist James Davies on 18 June 2008, adding, "The most important thing for me was being a woman and having a family more than being a very famous glamorous actress".