The Kiwi funnyman has become a cult hero for his role in Flight Of The Conchords as Murray Hewitt, the good-natured jobsworth who aspires to propel the titular band into the spotlight and who begins every three-man band meeting with a register.
The series started life as fellow New Zealanders Bret MacKenzie and Jemaine Clement's musical comedy act - billed as 'Formerly New Zealand's fourth most popular guitar-based digi-bongo acapella-rap-funk-comedy folk duo' - which they touted around live venues and festivals, eventually winning the coveted Perrier Comedy Award at Edinburgh Festival in 2003.
Rhys came on board when their act was turned into a comedy series for BBC Radio 2, and stayed for the ride when HBO offered to make it into a TV series, which promptly found its way back on to the BBC.
"We had this synergy," Rhys recalls of his time with Bret and Jemaine.
"We improvised a lot of band meetings and I loved working with the boys. It's unusual to find that."
Fans of the show have been dismayed to hear that there may not be a third series, after events of the ill-fated band and their manager were neatly tied up at the end of the second.
Rhys thinks it might have something to do with the pressure on the band to write three songs per episode.
He says: "They certainly enjoyed the writing process but the fact they had to pull together 20 new songs - that was the pressure, not that they didn't enjoy it but just that, as a musician, you don't want to be under that strain.
"That's why there's not many comedies around with individual songs. They started with three songs an episode so maybe they were signing their own death warrant, they should have just done one."
But he's adamant that it's not the "end of the end" and both he and Jemaine have suggested they'll team up again in the future for a special episode or even a film.
Meanwhile, Hollywood, family life and other promising new projects beckon.
Rhys has already made it on to the big screen with roles in Jim Carrey vehicle Yes Man and alongside Phillip Seymour Hoffman, Bill Nighy and Nick Frost in Richard Curtis's ensemble piece The Boat That Rocked.
He's now here to talk about The Amazing Dermot, a pilot episode for Channel 4 in which he plays the title character - a sleazy, deluded magician who can't help but put his foot in it at every turn.
So is this role the one which can help him make a break from Murray?
"Yeah, definitely," Rhys asserts.
"Yes Man was not a million miles away from Murray. My role was a slight step in a different direction but it was keeping in the same ballpark - a nerdy loser, and then in The Boat That Rocked I guess the character was quite nerdy, so to me it was important to not be a nerd again.
"I don't mind being a loser all the time but..." he says before stopping himself and putting on a whiney, victim's voice to add: "Look at me! 'I don't mind being a loser all the time but it would nice to be a winner once in a while'."
Rhys lets out a belting laugh, but he's serious.
He continues: "I knew that, as much as I can be a nice guy and I am a nice guy as a person, we all have more than one streak in us and I know I can really play the other side of the coin. I probably will surprise a few people with it. Dermot has empathy too and you have to have that in order to go with them. If he was a complete prick that you don't feel sorry for you wouldn't like him."
Dermot's first adventure sees him check himself into rehab as a publicity stunt after a high-profile magic trick goes wrong.
Also residing at the hospital is an unspeaking character called Edmonds, whose tendency to dole out mystery boxes gives viewers a big nudge as to who it's meant to represent.
But if the team behind the programme are worried about this, Rhys certainly gives no indication.
"They did clear it with him originally. As long as we call him Edmonds, people won't realise it's Noel Edmonds," he deadpans.
"He might be flattered at any mention of him on the small screen. If it turns into a very cool, popular sitcom as I think it's going to, he'll get a kick out of being in it, a bit like that neighbour in Home Improvement, the guy that was across the fence."
'If' is the big word at the moment for Rhys. The pilot is being shown as part of Channel 4's Comedy Showcase, a launch pad which has helped comedies such as Free Agents and Plus One land a spot on the channel.
If The Amazing Dermot gets a good response it may well be commissioned for a series, which will require him to move back to London.
This is no bad thing, Rhys reveals, as he misses the city in which he used to live as a stand-up comedian. Neither is it a problem to decamp his wife and young son.
He says: "The fact it was a UK project actually helped me make a decision because I felt like I had done my stuff in America, I moved back to New Zealand to bring up my child and to live and the other most important part of my life was in England. My son was born there and I lived there for six years so I felt part of my soul was there as well.
"My wife in particular loves London so it's a very easy decision. She was like, 'Oh yes let's go back there for two months!'"
The UK is also somewhat of a cultural heartland for the comedian who says his comic style is a result of a diet of golden age British comedy.
He says fondly: "I grew up watching Monty Python and The Goons. I was obsessed with classic British stuff so that was always my default mode. Doing stand up, I tried to be as original as possible which was pretty easy in New Zealand considering we didn't have much stand up."
He even thinks The Amazing Dermot has shades of the classics, giving him another reason to agree to take on the role that was written with him in mind.
He says: "He's sort of a cross between, and these are two of my favourite shows from the UK, Alan Partridge and Alan B'Stard from The New Statesman. I love both those shows, and this character screamed bits of these two people so it was a joy to see it and I just though 'this is perfect for me'."
Rhys Darby - Extra time
Rhys Montague Darby was born in New Zealand on March 21, 1974.
Rhys is currently on tour with his one-man stand up show. He describes his style as a "3D way of telling the story" and one reviewer described him as "a one-man special effect".
He and wife Rosie have a three-year-old son called Finn.
His Flight Of The Conchords character was called Bryan Nesbitt in the radio series, which changed to Murray Hewitt for TV.
He had only four days with a dialect coach to perfect a Yorkshire accent for Dermot's spitting image in the pilot of The Amazing Dermot.