Cashman will be reprising his role for two episodes and sharing scenes with "EastEnders" legend June Brown, who plays Dot Branning, reported Digital Spy.
"It was a real joy, indeed a privilege, to return to my old home of Albert Square. To be amongst so many friends again, and to be back in the place where 30 years ago I started an amazing journey," Cashman said.
"An amazing journey which incredibly helped to change the country, and certainly its attitude to lesbian gay and bisexual people."
Colin joined "EastEnders" in 1986 and is best remembered for his on-screen relationship with Barry Clark.
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