The actress, 72, played saucy waitress Yvette Carte-Blanche in the 1980s sitcom set in World War Two France.
Famed for her stocking-top flashes in the hit show, Essex-born Vicki will start filming for her new BBC soap role later this month.
She is due to appear for several episodes this spring.
A source said: “Bosses are keeping tight-lipped on her role, but she will definitely stir up some drama.
“Producers know she’s a talented actress and will go down a storm with fans.”
’Allo ’Allo! — which also starred the late Gorden Kaye as womanising café owner René Artois — ran for a decade from 1982.
It attracted 25 million BBC1 viewers at its peak.
Vicki played Patricia Foster in ITV’s Emmerdale between 2007 and 2009.
She was also in I’m a Celeb in 2014 and Celebrity Masterchef in 2008.
Last year, she defended ’Allo ’Allo! when a warning was slapped on repeats in case mickey- taking of French and German accents offended viewers.