Paul, who is the only son of Val Pollard and Rodney Blackstock, will be back in the Dales for a short stint of up to three episodes.
Matthew acted in the ITV soap from 2004 to 2009, and viewers also saw him briefly return in 2010.
Matthew, who has already filmed his scenes, teased fans on Twitter last night: "I couldn't find my way back to @Emmerdale but then this happened...! Phew!"
In the Twitter message, Matthew shares a video in which he questions what direction he's going in, before seeing a signpost for Emmerdale and the fictional town of Hotten, which is often referenced in the soap.
Bosses are keeping the details around his return top secret, but his arrival was announced as Nicola Wheeler, who plays his on-screen sister Nicola King, confirmed she was pregnant with her first child.
Taking to Twitter last night, Nicola - who only has a couple of weeks left before giving birth - said: "Very excited for @MathewBose's return to @Emmerdale, we all need a bit of Lambert love in our lives."
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