"Imran and Jemima have ended their marriage," an official of the cricket hero-turned-politician's Pakistan Tehreek-i- Insaaf (Movement for Justice) party said on Tuesday.
Confirming the separation, Imran, 50, said it was a mutual decision.
"I sadly announce that Jemima and I have divorced," Imran said.
"This was a mutual decision and is clearly very sad for both of us. My home and my future is in Pakistan," he said.
"Whilst Jemima tried her best to settle here, my political life made it difficult for her to adapt to life in Pakistan."
Jemima, the daughter of multimillionaire British businessman James Goldsmith, married Khan in May 1995. They have two sons.
Khan led Pakistan to victory in the cricket World Cup in 1992 and later formed his own party in 1996.