The British sailor won in the class at Rio 2016 alongside Saskia Clark, with the pair improving on their silver from London 2012.

Twenty-nine-year-old Mills will have a different partner this week at the Nautical Club of Thessaloniki, where she is due to team up with Eilidh McIntyre.

In June, the duo won the World Cup Final title in Santander in Spain, with Mills now returning to 470 after trying her hand in the 49erFX class.

"It's going to be hard," said Mills, who is expecting light winds. 

"In lighter winds it takes a while to get your feel back and I have been out of the 470 for so long."

Mills and Clark won the world 470 title in Barcelona in 2012.

The former will not face competition from any of her fellow Olympic medallists in Greece, and the three teams which made the podium at the 2016 World Championships in Buenos Aires will also be absent.

In the men's event, Olympic silver medallists Mathew Belcher and William Ryan headline a strong field.

The Australian duo won the 2013, 2014 and 2015 world titles before being forced to settle for joint bronze last year.

Croatia's defending champions and Rio 2016 Olympic gold medallists Šime Fantela and Igor Marenić will not take part, but London 2012 winners Belcher and Ryan can expect competition from the host nation and New Zealand.

Greece's Rio 2016 bronze medallists Panagiotis Mantis and Pavlos Kagialis will hope to impress on home water, while Kiwis Paul Snow-Hansen and Daniel Willcox are looking to turn their 2016 world silver into gold.

"We know what it feels like to race a good regatta," Snow-Hansen said to the New Zealand Herald. 

"We need to put it all together at the right time.

"We did some good work in New Zealand so we have given ourselves an opportunity." 

The Opening Ceremony will be held today before competition begins tomorrow.

Action will continue until July 15.