The pair were childhood sweethearts and McLoughlin was said to have brushed off the England footballer’s pleas for a date for a couple of years before caving in.
Official details of the wedding’s locations and even the exact date have been kept under wraps — but the couple are expected to exchange vows today.
The no-expenses-spared wedding bill is reported to be £5 million (€6.3m) and OK! magazine is said to have paid £2.5 million to cover the nuptials.
According to reports, the pair are expected to tie the knot at the Villa Durazzo, a cliff-top palace in Italy’s Santa Margherita and the same place Rod Stewart tied the knot with Penny Lancaster.
The Daily Telegraph’s website reported that Santa Margherita’s mayor, Claudio Marsano, is tipped to perform the service in the villa’s Salone Degli Stucchi room, beneath a Louis XVI chandelier.
The wedding party is then expected to proceed to La Cervara, a gothic abbey above Portofino, with the event climaxing with a huge fireworks display.
A source at Santa Margherita town hall was quoted on the Telegraph’s website as saying: “We have been asked to keep Villa Durazzo free for a wedding service for two British citizens, one of whom is a famous footballer.
“It’s actually proving to be a big headache.”
The 22-year-olds are said to have signed the paperwork earlier this week which allows them to marry in Italy.
McLoughlin’s Marchesa wedding gown is believed to have cost up to £200,000, and features pearls and crystals.
According to The Mirror, McLoughlin will make her sister Rosie a bridesmaid at her wedding, because she wants her to feel like “a princess” for the day.
The couple’s relatives and celebrity guests from the football world have been arriving in Italy all week.
Reports said the newlyweds and guests will board a luxury yacht with Westlife providing entertainment.
William Hill is offering 25/1 that the Rooney marriage lasts 25 years, 10/1 less than a year — and 5/1 on five years or fewer.
“We have had a few calls today about Wayne and Coleen and the length of their marriage but I don’t think any were from footballers as no-one wanted a vast sum on the outcome,” said Hill’s Rupert Adams.