It is the stadium where Taylor Swift inspired her adoring crowd to shake it off just two months ago.

A £300million arena whose main tenants are the Racing 92 rugby team and their new-recruit Owen Farrell.

But from 10.00 on Saturday morning, it will be the place where Adam Peaty begins his quest for his third gold medal in the 100 metres breaststroke.

For the next few days, the keys to La Defense Arena have been handed over to the swimmers of Paris 2024.

The rugby pitch has disappeared and, following an incredible 36-day transformation, it is now the temporary home of two Olympic swimming pools.

Paris’ £300m La Defense Arena has undergone a remarkable transformation in two months

Taylor Swift was performing here in front of an adoring crowd back in May for her Eras Tour

In a remarkable feet of engineering, they have installed two 50-metre basins – one for training and one for competition – pumped full with five-million litres of water.

The two 2.3m basins have been installed on top of Racing’s artificial rugby pitch – and the raised flooring means the front nine rows of seating have been removed.

It has been dubbed one of the world’s best swimming venues and, with advanced strobe lighting in place, it will feel like a 15-thousand capacity nightclub.

What would have been the half-way line on the rugby pitch is now a 22-metre high media tribune. It has been built using 20 kilometres of scaffolding, described as a ‘colossal’ achievement by event manager David Navizet.

‘At the time of the bid, there was a plan to build an ad hoc swimming pool in Seine-Saint-Denis,’ said Navizet. ‘There were a number of reasons for this change of direction: in the past, Olympic pools with a capacity of 15,000 have become white elephants because they are too big. We thought about building a pool with a demountable section, but that was too expensive. La Défense Arena was the most reasonable and efficient choice, and the gymnastics were moved to the Bercy Arena.’

The pools are 2.3m deep, featuring 10 lanes, made from stainless steel kits. Transporting in the materials has not been easy, requiring 10 trucks to carry the 358 steel panels through the heavy French traffic.

In total, they used seven tonnes of stainless steel components and 16,700 bolts. They have installed 450 metres of microperforated pipes, known as the Myrtha Breathe system, which are in place to maintain air and water quality.

The heavy-duty work is complete and on Friday afternoon, official timekeeper Omega were applying the finishing touches by testing the touchpads on the diving starting blocks.

Now Adam Peaty is one of many athletes hoping to claim glory in the Parisian venue