Shaun Williamson's new book reveals how his estranged son Gary managed to get in touch with him, years after becoming a fan of the actor's work.

Shaun Williamson, or Barry off 'Eastenders' as we like to call him thanks to his role in Ricky Gerais' comedy series 'Extras', has written an autobiography of his life which includes the incredible story of how he was put in touch with his son.

'A Matter of Facts' will release on October 1, and the Irish Mirror has learnt of how the connection between the father and son came about, which involves his mother being a member of a circus.

In 2013, Shaun received a letter claiming that Gary was his son, a child who was conceived during the actor's "circus days". It turns out that Shaun met Gary's mother in 1987 when she was working as a circus juggler, while he was 22 and working as a barman.

And yes, Gary was a huge fan of the actor even before he knew that he was his father, after watching him in 'Extras' as the assistant of Andy Millman's horrific agent, Darren Lamb (Stephen Merchant).

Speaking in the book, Gary says:  "My dad was in fact Shaun Williamson, an actor that I had admired for years, not from 'EastEnders' but from the sitcom 'Extras'.

"Me and my mates had even planned to go and see him when he was in a show at the Belfast Opera House some years before, so that we could meet him afterwards. How weird would that have been?"

Following this first contact, the actor underwent a paternity test which proved Gary was his biological son. The pair then met for the first time at a hotel in Belfast, with Shaun saying that they "hit it off straight away".

The actor added that Gary had said to him: "He said he never thought in a million years that Barry from 'EastEnders' could be his dad."

Along with the new addition to his family, Shaun Williamson also has two other children from his marriage to Melanie Sacre.

Here's an outtake from a moment in 'Extras' which caused the cast to corpse through a scene with a muffin.