Luxury watch brand Longines will sponsor the $4 million Queen Elizabeth Stakes, the richest race of the Sydney autumn carnival.

The Australian Turf Club announced on Saturday the naming rights and sponsorship was part of an extensive deal between the two.

The Queen Elizabeth Stakes (2000m) is at Randwick on April 19 with international actor Simon Baker, the Longines ambassador of elegance, scheduled to attend.

Under a five-year deal with the ATC, Longines will also have exclusive naming rights to the prestigious owners and trainers pavilion overlooking the Theatre Of The Horse at Randwick.

Longines will be the official timekeeper, and official watch of the Australian Turf Club and a Longines branded chronometer for official race timing will be installed at Randwick racecourse.

At the April 19 meeting, Baker will present the Longines Elegance Award to finalists selected from the Myer Fashions on the Field contest from April 12, Day One of The Championships.

"We are delighted to have Longines on board as an official partner of the ATC and we are confident they will be among more leading brands and companies who will want to be part of one of the world's truly great racing events," ATC chief executive Darren Pearce said.

The brand is also involved in some of the most famous racing events in the world including the Dubai World Cup, the Prix de l'Arc de Triomphe, Royal Ascot and the Melbourne Cup carnival.