The centre, founded in 1983, has become close to the singer's heart after her first visit, during which she said she "knew this place would become a big part of my journey". As well as being a patron, Lewis has now become a trustee for the sanctuary.
The walk is the first of many events which will be held as the 26-year-old aims to raise £100,000 for Christmas.
"A big ask, but one we can achieve by each just doing whatever we can for these animals that deserve some love," said Lewis, who had performed at the Michael Jackson Tribute concert in Cardiff the previous day.
The walk, which took the large group of supporters through streets of Brentwood and surrounding fields, raised £14,000 in donations.
Lewis told Digital Spy afterwards: "I'm so happy that everyone came out and supported us. Everyone is in good spirits, it's really nice! It went really, really well."
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Browse through our gallery of pictures of the sponsored walk below: