Hundreds of people including TV stars Richard and Judy braved the chilly evening and gathered outside the Castle to witness the annual event.
The famous couple were supporting daughter and Dancing on Ice star Chloe Madeley as she took to the stage in Castle Hill to help light up the town.
She was joined by former Bond girl Britt Ekland, comic Kevin Cruise, entertainer Anita Harris and actor Bradley Clarkson.
The quintet are preparing to star in the Theatre Royal production of Sleeping Beauty.
Proceedings began earlier in the afternoon with a lantern parade featuring children from St George's School and the Egham Brass Band.
Dozens of performers including Windsor Glee Club and the Rock Choir entertained the crowds during the course of the afternoon.
Carols were sung by the Choir of St George's Chapel, Windsor Castle, accompanied by Staines Brass, in the build up to the switch on of the town centre lights.
The lights also illuminate a giant Christmas tree, complete with a gold star, which is gifted by the Crown Estate.
Windsor and Eton town manager Paul Roach was pleased with the near-perfect weather conditions and the 'phenomenal' line-up at the event.
"We had a great night," he said.
He thanked sponsors Macdonald Windsor Hotel for all their help.
Shoppers also enjoyed an Italian market in the town centre over the weekend.
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