In Venice, in glistening sunshine, actor and director George Clooney and human rights lawyer Amal Alamuddin slid towards marriage on a boat named Amore.

He wore a dapper grey Armani suit, she a Dolce & Gabbana black-and-white striped dress (sold out), Prada sunglasses and D&G earrings (still available). It is believed her wedding gown is by designer Sarah Burton for Alexander McQueen, the designer chosen by the Duchess of Cambridge.

Also on board, as photographer-filled taxi boats churned the water, were Cindy Crawford and her husband, best man Rande Gerber, casual in denim.

The foursome, driven by Clooney's regular water taxi driver, could have been a Gap advertisement for the middle-aged, though a very glamorous one.

Also arriving in Venice for the multi-day celebrations were Matt Damon and wife Luciana Barroso, Ellen Barkin, Emily Blunt, Richard Kind and Anna Wintour, editor of US Vogue.

Expected were Brad Pitt, Angelina Jolie, Cate Blanchett, Bono and Sandra Bullock.

Wintour's presence suggested exclusive image rights to the wedding were probable, with reports all proceeds would go to Clooney's main charitable cause, Darfur in Sudan. A mobile phone ban was also requested.

The couple's main reception is to be held at at the Aman Canal Grande Venice, a 24-room "seven star" resort built in 1550 for the wealthy trading and seafaring Coccina family. In rooms costing up to €3650 ($5290), frescoes by painter Giambattista Tiepolo still exist.

A notice posted on Thursday announcing "matrimonio George Clooney" suggested that the pair will officially be wed in a civil ceremony on Monday at Ca' Farsetti, a 14th-century palazzo that houses Venice's town hall.

If it is all a practical joke, it is a very good one.

But Clooney, a known prank-puller, looked too at ease on the eve of wedlock to be pulling anyone's leg.