Mr Khan, once as celebrated a playboy as his father-in-law-to-be but now turning his back on all that, announced that Miss Goldsmith has become a Muslim. She had converted "through her own convictions" after studying Islam.
"As far as I am concerned, in Islam there are no boundaries of race or nationality. It is a universal religion. Both our families approve and are extremely happy about the match," he said in a statement after flying into London from Islamabad yesterday afternoon wearing a very Western uniform of T-shirt and jeans.
At her palatial wisteria-covered, wrought-iron-gated and cherub-decorated home, Ormeley Lodge, in Richmond, Surrey, Miss Goldsmith, an English student at Bristol university, made a less portentous statement to a waiting throng of reporters. Displaying her chunky half-inch-wide gold engagement ring featuring diamonds, sapphires and rubies, she smiled and said: "I'm very happy."
Later her mother, Lady Annabel Goldsmith, smiled and said: "I'm thrilled."
Then soon afterwards, a spokesman for Sir James came out of the house, unsmiling, to deny rumours that Jemima was pregnant. "It's absolute rubbish," he said.
Suntanned with long blonde hair, and yesterday dressed in tight jeans and a low-cut white T-shirt, Jemima Goldsmith may be a beautiful bride, but she may not be the image of womanhood to further Mr Khan's hitherto burgeoning Pakistani political career.
One close observer of the Pakistani political scene said: "Imran's chances of entering politics on any kind of conservative platform will be shattered by this. It is very difficult to reconcile with his condemnation of Western culture and his insistence that Pakistanis should take pride in Islamic culture.
"Even if his wife became a Muslim, it would be no good as long as she remained a modern woman. To satisfy conservatives, she would have to wear the veil at all times and keep to her home."
The interest in Mr Khan's nuptials highlights the two distinct worlds in which he lives. In Britain it is tabloid news of a high society event. In Pakistan the marriage has implications for the nation's future. The man once thought of as sport's most eligible bachelor has been aiming at a political destiny.
Since retiring after Pakistan's World Cup victory in 1992, Mr Khan has devoted himself to raising money for the cancer hospital he founded in Lahore in memory of his mother. He also renounced his playboy past, began wearing the traditional shalwar kameez rather than Western clothing, and spoke out against corruption and the indifference of the rich towards the poor in Pakistani society.
Jemima Goldsmith was the first child of the illicit affair between Sir James and Lady Annabel Birley, when he was still married to his French secretary Ginette. Sir James and Lady Annabel - she was the younger daughter of the Marquess of Londonderry - married in 1978 when Jemima was four.
Sir James Goldsmith, 62, is the son of a German Jew and a French woman. In the 1970s he built up a huge food empire based in Britain and France. More recently he has achieved prominence as a member of the European Parliament.
Miss Goldsmith is believed to have known Mr Khan for about a year, but their relationship was unpublicised prior to Friday night's wedding announcement issued by a PR firm.
It may finally bring to an end his reputation as a sex symbol, gained by escorting a long line of very visible women, including the model Marie Helvin, the actress Goldie Hawn and the German MTV presenter Kristiane Backer.
Recently he talked at length about marriage and the difficulties of finding the right partner. "At my age it's about finding the right sort of woman with the same ambitions," he said.
"She doesn't have to be the same race but it would help if she was Muslim. I have been with some very beautiful women and admit that I had a reputation as a playboy. But my efforts are being concentrated here in Pakistan."Reuse content