Justin Timberlake says seeing Jessica Biel in her wedding dress was "the most beautiful thing".

The pair wed in front of family and friends at a private ceremony in southern Italy on Friday.

Jessica, 30, wore a custom-made, pink Giambattista Valli Haute Couture gown during the nuptials at the Borgo Egnazia resort in Puglia.

"It was a really special evening," Justin gushed to People magazine. "[Jessica was] the most beautiful thing I have ever seen."

"It was a total fantasy experience," Jessica added.

The nuptials included a touching moment where Justin, 31, serenaded his long-term love as she walked down the aisle in her stunning dress.

Justin wore a Tom Ford tuxedo as he played the guitar and sang to Jessica.

"It was an original piece I wrote specifically for the evening and for her," he explained of the song.

The couple kicked off their celebrations with a party and firework display at Cala Masciola beach last Wednesday.

The festivities were laid on for guests who travelled to Italy, including singer Timbaland and Jessica's 7th Heaven co-star Beverley Mitchell.

"It was a lot to ask of them to travel, so we figured we'd give our guests a good party!" Justin explained.

Justin and Jessica began dating in 2007, and the SexyBack singer proposed to the actress during a romantic trip to Big Sky, Montana, last December.