Justin Timberlake and Jessica Biel

Justin Timberlake serenaded Jessica Biel on their wedding day.

The 31-year-old singer-and-actor sang one of his previously unreleased songs at the couple's nuptials in southern Italy on Friday - which saw The Roots' drummer Questlove DJ at the reception - and he dedicated the performance to his new wife.

A source told Us Weekly: ''Questlove played a bunch of Justin Timberlake songs, but no *NSYNC. Justin performed one song at the wedding. It's a new one that he hasn't released yet. He dedicated it to Jessica.''

The couple decorated the ultra-exclusive Borgo Egnazia resort in Puglia completely in white floral arrangements for their big day and even inside of the private hotel complex, where the reception was held, was ''draped in white and filled with white flowers''.

An eyewitness said: ''Even the balconies facing the main courtyard were dressed with white blooms. Small white heart shaped petals fell on the couple as they left the chapel.''

Andy Samberg, Jimmy Fallon and Beverley Mitchell all attended the couple's nuptials, and Justin - who has been dating the 30-year-old actress for around five years - admitted it was ''magical''.

He said: ''It was magical. It was an unforgettable evening.''

Jessica added: ''It was a fantasy.''

© Bang Showbiz