John will be reprising his role for another brief stint on the BBC soap alongside Lynda Baron, in what is being tipped as an "explosive storyline involving the Beale family".
While John will be back as Jane's brother Christian, Lynda will return as Jane's mother Linda Clarke.
Christian, who appeared on series 17 of Celebrity Big Brother, was last seen in Albert Square last year when he attended Ian and Jane's wedding as part of the live 30th anniversary week.
Speaking about his return, John said: "I am thrilled to be able to return to EastEnders whilst touring the UK with Chicago… Christian is never far from my mind - I turn my back for five minutes and look what happens!"
Bosses are staying tight-lipped on the details surrounding their return, but we're told the storyline will "change the Beale family forever".
Jane's mother, Linda, has not been seen on screen since February 2009 when she moved to Florida with her husband, Roger.
Christian and Linda will return to Walford early this summer.
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