'The Whole Scene Was Just A Kerfuffle': Casey Donovan Reveals The Word That Broke Peter Helliar

Joining the cast of How To Stay Married for Season 3, Casey Donovan says there was one scene she and her co-stars struggled to get through.

Peter Helliar called her the secret weapon of the show's third season, and Casey Donovan is a revelation as she steps into the role of Luna Keys, a character even Casey admits you "love to hate".

"She's got a very big heart, but she just comes across in all the wrong ways," Casey told 10 play.

The President of the Parents and Friends Committee, Luna is everything that Greg Butler is not. Throughout the season the pair have butted heads and traded passive-aggressive barbs and thinly veiled insults through gritted teeth.

Luna's the kind of parent that prepares fresh dumplings for her son, she's securing gold-tier prizes for the school-run trivia night and she's bringing Olympians to be on her team.

"It is so much fun to play," Casey added. "She's a proud mother and she's literally got her finger in every pie but unfortunately starts butting heads with Greg and their rivalry is just great to watch, and it was also great to be a part of."

Casey Donovan How To Stay Married Season 3

In an earlier interview, Peter told 10 play that Casey's approach to playing Luna was so wholly realised it would often lead to him breaking into fits of laughter during their scenes.

"There was this one scene," Casey said, "they're at the library and Luna rocks up because she's getting [her son] Clarence ready for University even though he's in year six. So, she's bumped into Em and Greg and she just throws him this look.

"I looked at Pete and I've just gone, '...Greg' and from that moment, that whole scene was just a kerfuffle. On the reverse [shot] he was just losing it," Casey said, cackling. "I was like, keep it together Pete!

"I think it made the blooper reel," she added, still laughing.

There's a physicality Casey embodies playing the role that is both a caricature of and perfect distillation of that person we all know.

"A few people have come up and said, 'You remind me of Linda so-and-so from where my kids go to school,'" Casey said adding, "I'm guessing there are a lot of Lunas out there."

Though she's able to crack up her co-stars, Casey teased that Luna is far more than comic relief, describing hers as a "beautifully sad" story.

"She just has all this love to give and I think love, for her, comes out in the wrong ways. She wants to be people's friend but she's also very guarded, and I found that so interesting to work into her character."

From Luna's fearlessness when it comes to confrontation to the way she weaponises the word sh*t, Casey has started to notice bits of Luna she's taken away from the set and brought into her own life.

"When you do so many characters throughout the years you're like, oh god am I still being true to who I am as a person? And yes, you are, but you do snap little branches off and go, alright. I can learn from that.

"I would never think to rock up at someone else's house and accuse their child of stealing, like who does that? Luna does."

Having fallen in love with Luna, Casey said she hoped to do more work on the small screen very soon.

"I loved working with Pete and all the crew," she said. "They made it safe and Australian TV is an amazing thing to be a part of. I'm so grateful for the opportunities, and I'd love to do more."

How To Stay Married airs Tuesdays after MasterChef on 10 And 10 play