Singer Leona Lewis and London mayor Boris Johnson are to open Europe's biggest inner-city shopping complex in west London.
The Westfield Shopping Centre in White City boasts more than 1.6m square feet of space - or around 30 football pitches. It cost £1.6bn to build over the past five years.
Among the 265 retail units are just about all of the UK's high street giants, including Debenhams, Next, Marks & Spencer, House of Fraser and Waitrose.
Around 80% are fashion-focused, with the site featuring 40 luxury brands including Louis Vuitton, Mulberry and Prada housed in a boutique-style environment called The Village.
There are also around 50 restaurants, as well as a multi-screen cinema.
Currently 99% of the retail space is let, with 80-90% of the building open for Thursday's launch.
Westfield, which is the UK's third biggest shopping centre after Gateshead's MetroCentre and Bluewater in Kent, is opening for business just as the UK slides into a widely-predicted recession.
The centre took 13 million man hours to build, has 96 escalators and is expected to have created around 7,000 jobs - with 1,000 going to local residents.
Bosses estimate 21 million people will visit the centre each year, with a cash register expected to ring every 30 seconds.
Copyright Speakers Corner 2016