Born in Libya to Pakistani parents, mother-of-three Reham lived in Britain while married to a doctor and worked for the BBC's South Today programme.
Imran is understood to be spending three days in Britain. His romance was opposed by some members of his family and now has become a highly contentious topic in Pakistan, where he is a leading politician.
Reham has already been subjected to insults after photos of her in ‘revealing' clothes and a video of her dancing the tango were posted on the internet in the conservative Islamic country.
Jemima, who converted to Islam before marrying Imran in a traditional Muslim ceremony in Paris at the age of 21, told the tweeter: ‘Really touched by these messages.'
Jemima announced last October that she was ditching the Khan name because Imran was soon to remarry.
Imran said their marriage collapsed because it was ‘difficult for Jemima to adapt to life in Pakistan'. Reham, who is said to have political ambitions of her own, should have no such problem.