The 52-year-old filmmaker was married to the Pakistani cricketer-turned-politician for around nine years before their divorce in 2004. The couple have two sons together, Sulaiman and Kasim, who have been campaigning on behalf of their father's health while he languishes in prison in Rawalpindi
"Celebrating Jemima and Cameron's wedding, with my favourite date, what a happy day," Jemima Jones, the wife of Jemima Goldsmith's brother Ben, said in a post on Instagram while posing with her husband
O'Reilly, a 62-year-old Irish Australian businessman, and Jemima Goldsmith are believed to have exchanged their wedding vows at an elegant ceremony over the weekend.
The newly married couple are believed to have met through their shared interests in film and documentaries.
Jemima Goldsmith, founder of the production company Instinct Productions, has written and produced several shows and films, including the cross-cultural romantic comedy directed by Shekhar Kapur, 'What's Love Got to Do with It?'.
She has also edited and written for publications such as 'The New Statesman' and 'Vanity Fair' and is outspoken on human rights issues.
Last month, she took to social media on behalf of her ex-husband's incarceration in Pakistan and in support of her sons' campaign.
"This is no longer simply a Pakistani political matter. It is a human-rights emergency," she wrote.
She said: He has deep and lifelong ties to Britain. He studied at Oxford University, captained Oxford University cricket and spent years playing county cricket in England. His relationship with this country stretches back more than half a century. His charitable activities were internationally recognised, and include building the only free cancer hospital in Pakistan as well as a university.
"His sons, my two boys, Sulaiman and Kasim, are British citizens. They have been forced to watch their father's health decline from thousands of miles away, prevented from visiting him, denied visas, publicly threatened by government officials with arrest themselves, and even denied court-mandated regular phone calls."