From StarWars.com:
Billy Dee Williams (Lando Calrissian, The Empire Strikes Back & Return of the Jedi)

David Ankrum (Voice of Wedge, A New Hope, The Empire Strikes Back, Return of the Jedi)

David Barclay (Jabba the Hutt puppeteer, Return of the Jedi)

Lightning Bear (Scout trooper and stormtrooper, The Empire Strikes Back and Return of the Jedi)

Sean Crawford (Yak Face and Mon Calamari officer, Return of the Jedi)

Dermot Crowley (General Crix Madine, Return of the Jedi)

Tim Dry (J'Quille (Whiphid) and Mon Calamari, Return of the Jedi)

Mike Edmonds (Logray the Ewok and Jabba the Hutt puppeteer, Return of the Jedi)

Christine Hewitt (Tonnika Twin, A New Hope)

Barrie Holland (Imperial Officer, Lt. Renz, Return of the Jedi)

Ian Liston (Lt. Wes Jansen and AT-AT Driver, The Empire Strikes Back)

Toby Philpot (Jabba the Hutt puppeteer Return of the Jedi)

Matt Sloan (Plo Koon, Attack of the Clones, and Revenge of the Sith)

Shannon McRandle (Mara Jade, Star Wars trading card game)

John Mollo (Costume Designer and Academy Award Winner, A New Hope, and The Empire Strikes Back)

Brian Muir (Sculptor, A New Hope)

Joe Viskocil (Visual Effects (Pyrotechnics), A New Hope, The Empire Strikes Back)

Danny Wagner (Mawhonic, The Phantom Menace & ILM Model Maker, The Phantom Menace, Attack of the Clones, and Revenge of the Sith)

You can find out more @ CelebrationEurope.com

See also:
Warwick Davis To Host Celebration Europe