The pair made their vows in a 20-minute service at 9.30 this morning in the 17th century Villa Durazzo.
The town's deputy mayor, Gianni Costa, who performed the ceremony in Italian, said there were about a dozen family members present as well as a translator.
Insiders say no rings were exchanged and that Coleen burst into tears of joy when it was complete.
The newlyweds then moved on to at a 900-year-old church where they were blessed by family priest Ned Quinn.
Exact details of the £5million wedding have been kept secret after a reported £2.5million magazine deal.
Meanwhile, a picture has emerged of what appears to be Coleen sheltering from the rain in a white dress this morning.