A representative for Hounsou, who has been dating Lee Simmons since 2007, announced the sad news on Wednesday (21Nov12) after weeks of speculation suggesting the couple's romance was in trouble.
The rep tells People.com, "Djimon Hounsou and Kimora Lee Simmons have officially separated after five and a half years."
Lee Simmons and the Blood Diamond star never officially wed, but they staged a traditional commitment ceremony in Hounsou's native Benin in 2008.
They are parents to a three-year-old son, Kenzo. Lee Simmons is also mum to two daughters from her marriage to music mogul Russell Simmons.