The former Shameless actor will join the Square as Tony King, boyfriend of Bianca Jackson (played by Patsy Palmer).
But there's a dark side to the former jailbird, as he's exposed as a paedophile who takes an unhealthy interest in stepdaughter Whitney Dean (Shona McGarty).
'This is the most challenging role I have had to play,' Chris, 34, says.
'But I hope by EastEnders tackling the sensitive issue of child abuse it can raise awareness.'
Chris's former Shameless co-star Maggie O'Neill also joined Albert Square recently as Suzy Branning.