The celebrity couple were greeted by a crowd of about 200 who had gathered outside the McEwan Hall, just after 4pm.
The actor and film-maker returned to the capital along with his wife, an international human rights lawyer, to attend the People’s Postcode Lottery Charity Gala.
They were being honoured for their international humanitarian work through the Clooney Foundation for Justice.
As George Clooney signed autographs and took selfies with the crowd, he said: “They told me it was going to be a warm day.
“Make sure you stay warm out here.”
Speaking to STV’s entertainment reporter, Clooney said it was “fantastic” to be in Edinburgh and that the lottery does an “unbelievable” job.
He said: “The idea that an entire neighbourhood can have a great time and make some money, and in the meantime (help) hundreds and hundreds of charities across the world. I mean, it’s a spectacular thing. I wish we’d do it in the States.”
And he quipped that it was the first time he’d seen the sun since being in Scotland.
Onlookers were especially wowed by Amal’s beauty as she dawned a dark blue dress on the red carpet.
Just before heading inside, the couple also met Nice Nailantei Leng’ete, a human rights and female genital mutilation activist and ambassador for charity AmRef.
Nice was named in Time Magazine’s world’s 100 most influential people of 2018.
British TV presenter Fiona Phillips was also in attendance at the event and spent time speaking to the crowd and signing autographs.
Also present were Boudewijn Poelmann and Annemiek Hoogenboom, founders of the People’s Postcode Lottery. They were joined by Clara Govier, managing director of People’s Postcode Lottery.
The Clooneys follow the likes of Sir David Attenborough, Dame Emma Thompson and the Prince of Wales, who have previously been honoured by the charity.
Hundreds of people turned out to welcome George Clooney in Edinburgh when he visited Social Bite and the headquarters of the People’s Postcode Lottery in November 2015.
Players of People’s Postcode Lottery have already raised £1.3m for Clooney’s human rights charity, Not On Our Watch, which he founded along with fellow Hollywood stars including Brad Pitt and Matt Damon.
The annual Charity Gala is a celebration of the work done by the charities which are supported by the lottery’s players.
In total, players have raised more than £400m for charities and good causes since 2005.
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