Simon confirmed the news to the Daily Mail, stating: “We are both so happy, as are our children.”
According to The Sun, the couple have been an item since early 2020, and now live together in the Cotswolds.
The former BBC News anchor added: “We shall celebrate in the spring, when it’s safe to share a party.”
Simon is best known for his work at BBC News, having gone viral for several of his live broadcasts, including quips about the Royal Family and one infamous occasion in which he read the headlines while holding a ream of paper instead of an iPad.
He was previously married twice before, including to fellow BBC presenter Victoria Graham, with the two splitting after 11 years in January 2019.
Earlier this year, he surprised many when he announced his resignation from the BBC after 18 years, confirming shortly afterwards he had signed up to present a show on the ill-fated GB News.
While he initially co-hosted an afternoon current affairs show with Alexandra Phillips, he has since been moved to the morning show the Great British Breakfast, which he presents with Kirsty Gallacher.
Meanwhile, Emma is most famous for playing Fallon Carrington Colby in Dynasty and Holly Sutton in the US soap General Hospital.
Her marriage to Simon will be her fourth, having previously wed Bansi Nagji, Tim Dillon and John Holloway, with whom she shares two children.
Simon also has a grown-up son from his first marriage.