The actress-turned-TV-chef has been cast as new character Fi Browning in the BBC soap.
She is described as a “stylish, sophisticated businesswoman”, who is sure to shake up Albert Square.
Lisa said in a statement: “I’m so happy to be joining the cast of ‘EastEnders’ – it’s an iconic show and I can’t wait to play my part in it.
“Fi Browning is a hugely exciting character and I’m really looking forward to working with [producer Sean O’Connor] and all the team, and revealing more about her. I can’t say any more now as I’m sworn to secrecy, but it’s going to be a lot of fun.”
Teasing her character, executive producer Sean added: “Fi Browning is something of a departure for ‘EastEnders’; a no-nonsense but sophisticated businesswoman with strength and vulnerability.
“But does she have an agenda? And who - or what - has she set her sights on?”
Lisa - who shot to fame as Louise Hope in defunct Channel 4 soap ‘Brookside’ between 1997 and 1998 - has previously starred in dramas including ‘Spooks’, ‘Dangerfield’ and ‘Murder In Suburbia’.
She was also one of the original members of the ‘Holby City’ cast, playing Dr Victoria Merrick from 1999 to 2001.
Since winning ‘Masterchef’ in 2010, Lisa has gone on to publish a number of cookbooks, as well as appearing as a chef on ‘This Morning’.
She also found love with ‘Masterchef’ judge John Torode, who she has been in a relationship with since 2014.
Her casting in ‘EastEnders’ follows the recent announcement Blue singer Lee Ryan is also joining the soap as ladies’ man Woody Woodward.
Both stars are due to made their debut in Albert Square later this year.