Music producer David Foster and singer/actress Katharine McPhee have become husband and wife.

The couple wed in an intimate ceremony at the Church of Saint Yeghiche in South Kensington, London on Friday, according to Us Weekly.

The bride, 35, walked down the aisle in a custom dress by top designer Zac Posen, and exchanged vows with David, 69, in front of 100 guests.

Shortly before the nuptials, Katharine took to Instagram to share a video clip of herself onstage back in 2006, after finishing as the runner-up on TV talent show American Idol, and revealed the significance of their wedding date as she reminisced about the history of their relationship.

"Exactly 13 years ago today my very first single, Somewhere Over The Rainbow, was released right after Idol," she wrote in the caption.

"Today... I'm marrying the man who produced it. Life is full of beautiful coincidences, isn't it? Thank you for taking me over the rainbow, David."

The couple first sparked dating rumours in early 2017, but repeatedly played down its relationship until last year, when David and Katharine made their romance red carpet official at the Met Gala.

They announced their engagement just two months later.

The marriage is Katharine's second, following her divorce from Nick Cokas in 2016, and David's fifth.

He was previously married to Linda Thompson, Rebecca McCurdy, B.J. Cook, and model Yolanda Hadid, who he divorced in October 2017.