"It is very exciting and surreal at the same time being back on set again, however it feels like coming home," the actor, who played heart-throb Mike Young on the show, said in a statement.
"It’s where it all started for me professionally. I’ve been asked to come back on occasions over the years and wondered if it was the right thing to do, but once I knew the show was finishing, I knew I had to do it. While I’ve caught up with many of the cast I worked with on the show over the years, there is nothing like being here all together again."
It comes following the announcement that much-loved stars Kylie Minogue and Jason Donovan are set to reprise their roles as Charlene and Scott.
Fans shared their excitement on Instagram with many simply commenting, "OH. MY. GOD."
"Gasp. Squeal. Mike!" one excited fan wrote.
"MY PRAYERS ANSWERED!!!!" another added.
"Ahhhhh was hoping for Mike after Scott and Charlene," a third said.
"I’m so happppoooyyyyyy," someone else wrote.
Many others thought the news was bittersweet, with one writing, "Just such wonderfully amazing news but also so so sad."
"Absolutely devastated Neighbours is ending after watching since 1986, but these cameos are doing Ramsey St proud!" another said.
"I know I should be happy, but all I think is it's ending," a third wrote.
Jason Herbison, Neighbours’ Executive Producer, said, "I’m incredibly honoured that Guy is returning to the show for a very special story arc. Having him back on set has been poignant for him and for us. He’s been very involved in the storyline, and I can’t wait to finally answer the question for viewers — who is Mike Young today?"
Guy was on Neighbours for four years before heading off to Hollywood and starring in hit films such as Memento, LA Confidential, Iron Man 3 and more.
When the news that Neighbours would be cancelled after 37 years was shared, Guy took to Twitter to write, "I’m so sorry to hear Neighbours will end. Aside from being the incredible launch pad it’s been no one can deny the effect it’s had throughout millions of homes around the world.
"It’s bonded all of us in immeasurable ways. A true honour to have been a part of it. Great memories."
The show was cancelled after the UK's Channel 5 pulled out their funding for the show.
A petition was launched the save the show, however, with no alternative funding the production had no choice but to wrap up.
The final episode of the show will air on August 1 on 10 Peach.
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