The 'Collide' star became a trustee and patron of Brentwood's Hopefield Animal Sanctuary when it was threatened with closure. Aiming to raise £100,000 by the end of the year, Lewis has supported a number of events to help reach the target figure.
Last month, she joined fans and supporters on a five-mile walk, which raised £14,000. A Christmas fete and carol event will also be held over the coming month.
This Saturday (November 19), the 26-year-old will host 'An Evening with Leona Lewis and Friends' at a private residence in Beverly Hills. Featuring performances from herself and friend Natasha Bedingfield, guests will also enjoy cocktails and canapes.
Among those expected to attend are X Factor USA stars Nicole Scherzinger, Paula Abdul and Steve Jones, Glee's Matthew Morrison and Kevin McHale, Rob Kardashian and Kristin Cavallari.
Lewis recently announced a competition offering one fan the chance to design her outfit for an upcoming major television performance.
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View pictures from Leona Lewis's visits to Hopefield Animal Sanctuary below: