The revelation comes in a new documentary from the British broadcaster that will be broadcast on Wednesday. In it, Farah also says that his real name is Hussein Abdi Kahin and that he was born in Somaliland.
“Despite what I have said in the past, my parents have never lived in the UK,” Farah told the BBC.
He says the family was “torn apart” after his father was killed in the Civil War when he was just four years old. Somaliland declared its independence in 1991 when it broke away from war-torn Somalia, but has never been recognized as a sovereign state.
“I was separated from my mother and I was illegally brought into the UK under the name of another child named Mohamed Farah,” he said in a clip of the interview.
Once he arrived, he said he was forced to “do housework and childcare.”
A few years later, he was finally allowed to go to school, where he confided in his situation to a gym teacher. The teacher contacted social services and Farah moved in with a Somali foster family.
“I still missed my real family, but from then on everything got better,” he told the BBC.
Farah, who received British citizenship in 2000, says running saved him from a life of servitude.
CNN has reached out to representatives for Farah for comment.