The character was involved in a number of high-profile storylines – most famously the death of her husband, Barry Evans, who she pushed down a cliff during a trip to Scotland in 2004.
Brooks, 40, said in a statement: “I am beyond excited to be slipping back into Janine’s shoes and returning to the square. The time feels right and I can’t wait to find out what she’s been up to for the last seven years!
“She is and always has been SO much fun to play. Feels a bit like coming home. It’s good to be back.”
On her Instagram page, Brooks said there is “so much in store” for her character.
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EastEnders executive producer Jon Sen described Janine as “one of EastEnders’ most iconic characters who is loved, and often despised, in equal measure by viewers and all those in Walford”.
He continued: “Charlie’s portrayal of Janine over the years has created some of EastEnders’ most memorable moments and we are all really excited to see Charlie bring her incredible portrayal of Janine back again.