Zoe Saldana, one of the stars of Avatar, the biggest box-office film in the history of movies, has ended her relationship with fiance Keith Britton, the website of television channel CBS News said.Saldana and Britton \"have amicably separated after 11 years\", the actress\'s agent said.The 33-year-old actress and Britton, a businessman of 35, announced their engagement in June 2010.The agent\'s communique said that the two will continue as partners at the head of My Fashion Data Base.Saldana, one of the Latino stars with the greatest presence in Hollywood thanks to her roles in Star Trek, The Losers and above all Avatar, premiered Colombiana in August, a madcap action film directed by Olivier Megaton.