Shortland Street star Pua Magasiva's tearful wedding to Lizz Sadler

On the morning of Pua Magasiva's wedding, it's bucketing down. Plans for an outdoor ceremony have been ditched, with a white marquee erected on the soggy lawn of the riverside Auckland venue as the rain pounds down.

Making matters even more fraught, the power is still out five days after a violent storm hit the region, so historic tavern The Riverhead is running entirely off a generator.

But as the guests trickle in and bride Lizz Sadler prepares to make her entrance, miraculously the skies clear and the bunch of white umbrellas Woman's Day has brought along are suddenly redundant.

However, moments later, the groom collapses against a wall in tears. Amid the crowd of guests, the Shortland Street actor and Flava radio host, 37, has spotted his twin brother Tanu, who had been scheduled to undergo heart surgery in Wellington and wasn't going to attend.

Unbeknown to Pua, the operation was postponed and Tanu secretly travelled north. Composing himself, the Samoan-born star tells us, "Oh, man, I lost it just then. It means everything to me for my twin to be here. We're like yin and yang, but he's always had my back and made sure I felt safe ever since we were born. This is the best surprise."

But the tears aren't over yet. As Pua, in a custom white linen suit from Hallensteins, and his groomsmen wait at the altar, the best man, Pua's cousin Fa'atonu Fili, sings a tune he wrote about the bride and groom's relationship. "Though we've had some ups and downs, we've made it through somehow," he croons while the gorgeous tutu-clad flowergirls, Pua's daughter Jasmine, seven, and Lizz's girl Laylah, six, sprinkle white rose petals down the aisle.

"When I look in your eyes, all I can see is my forever," he continues as the bridesmaids file in wearing pretty pastel-blue chiffon dresses.

Then there's a collective gasp as a serene, radiant Lizz, 31, in a figure-hugging, mermaid-shaped Jane Yeh dress made of ivory French lace, with a long, dramatic train, enters the marquee on the arm of her father.

As he'd predicted before his big day, the groom is already wiping away tears. Later, Pua explains, "I was so caught up in emotion. She looked like an angel. I couldn't believe how beautiful she looked – and the fact she was dedicating her life to me."

When they meet at the altar, under an arch decorated with palm fronds and white roses, the glowing couple clasp each other's hands and whisper loving words.

Afterwards, Lizz recalls, "I thought I'd be really nervous, but I was so happy. And Pua wasn't hysterically sobbing, so that was good too! I was wearing the necklace he'd bought me before the wedding, and I told him I was glad he was wearing the watch and fragrance I'd got him. His lucky number is 14, which is why we married on the 14th, and I'd written him a note with 14 reasons why I love him, so he was telling me how much he appreciated that."

Following a Samoan welcome to the 125 guests, the celebrant, Pua's good friend Siona Tulia, discusses the "new family unit" the couple are creating today, and speaks of the "social media world" that brought the bride and groom together.

Pua, who's played nurse Vinnie Kruse on Shorty since 2003, first laid eyes on Lizz on Instagram in October 2016, when she innocently followed him. Despite having almost 90,000 admirers on the app, the actor instantly took notice of the beautiful blonde and the sweet snaps she shared of her daughter, and they began swapping messages. Just 10 months later, last August, Pua surprised the primary school teacher by popping the question on a snow-capped peak above Queenstown during a romantic helicopter flight.

It's been a whirlwind romance, but the star insists, "I was listening to my heart. When I proposed, I knew it was the right thing to do."

After Jasmine and Laylah hand over the rings, Pua and Lizz exchange the vows they've written together, promising, "If we should stumble, we will work together solidly and as one. We will always have each other, our beautiful girls and, most importantly, our love."

Then it's on to some more tongue-in-cheek pledges they've written separately, with Pua bringing the house down when he swears,

"I promise to try to not eat with my mouth open, to not bite my nails and not pick at my feet – only yours because I have a weird fetish like that. And to keep my singing to a minimum, even though it's good, especially the high notes you like. I'll also try not to snore too loud, fart in front of you, scuff my shoes or make weird noises. Um, actually, I'll shut my mouth, not move at all and just love you always, shall I?"

Then, speaking together again, the bride and groom pledge, "I swear to share everything with you as you are my everything. I will treasure you and encourage you, be open with you and true to you for eternity."

Afterwards, Pua and Lizz sign the official papers, with his twin Tanu and her sister Virginia Peek acting as witnesses while the Starship hit "Nothing's Gonna Stop Us Now" plays. Pua later explains, "There's a line in that song that goes, 'Let them say we're crazy. I don't care about that.' It's a close representation of our relationship because we're really passionate, full-on and a little psycho with each other."

After a Samoan blessing, the couple are pronounced husband and wife, and the guests cheer raucously as the newlyweds share a long, lingering kiss to the sound of "You Are" by Lionel Richie, who they'd seen live in concert just a few days earlier.

Later, Lizz tells us, "I'm so happy it's official. We've always been committed to each other and don't really need a piece of paper, but it's so important to do this in front of friends and family, and for our girls, who are excited about having an actual stepmum and stepdad. It feels good to be Mrs Magasiva."

Following the ceremony, guests are seated for Samoan entrees of raw fish, pork belly and mango salad, and given goodie bags with mini bottles of L&P (Lizz and Pua!). Then the MC, Pua's Sione's Wedding co-star John Tui, introduces the flowergirls, who kick off the speeches in adorable fashion.

Reading from notes, Jasmine tells the bride and groom, "I just want to wish you two a happy and fun life. Congratulations. Love you guys!" Her new stepsister Laylah adds, "I hope you are having a fantastic day at the wedding."

After the applause dies down, John declares, "They're the most coherent people in the room and that was the best performance – sorry, Shortland Street actors." The quip goes down a treat with many guests, including Pua's brother and former co-star Robbie Magasiva, current Shorty stars Ben Mitchell, Jarod Rawiri, Luke Patrick and Lukas Whiting, as well as ex-castmates Te Kohe Tuhaka and Frankie Adams.

In his speech, Pua's Flava co-host Sela Alo tells the bride, "You deserve someone who is gentle, kind and has nice fingernails. I'm sorry Pua has none of these. But at least he's got good muscles – and when I see you together, you're both so happy. Now it's time for me to teach Pua to dance properly so you can be even more happy!"

Then – while guests tuck into their mains of scotch fillet, Akaroa salmon or kawakawa chicken – the groom pays tribute to his bride in an emotional speech, declaring, "We've been through hell and back, but we've survived purely because of love. A lot of people have asked how we could get engaged after less than a year, but for both of us, it was an instant connection. I was never able to deny it and I was always going to be here for you, baby, through thick and thin.

"We made it work and we will continue to strive to make it work. Relationships aren't always easy, but you've got to fight for your love. At the end of the day, all that matters is me, her and our kids. We'll love each other until the bitter end."

As Pua finishes to loud cheers, Te Kohe leads fellow actors Ben, Jarod and John in an impassioned haka. Then the newlyweds hit the floor for their first dance to Hawaiian artist Siaosi's song "Everything is Good".

Now in full party mode, Flava's DJ Manchoo hits the turntable and the Shorty stars bust out their moves.

Taking a break from twerking, a barefoot Frankie, who has flown in from Los Angeles, tells us, "This has been the best night. Pua's like my big brother and as soon as I saw these guys together, I knew they were infatuated – in a healthy way! I'm so happy and so proud."

Pua's brother Robbie, and star of Wentworth, who has jetted over from Melbourne, agrees, "It's all about family and it's been a gorgeous day. I'm here for my little bro. Lizz makes Pua happy, and that makes me and my little niece happy."

Shorty star Ben, attending with his heavily pregnant fiancée, adds, "I love this wedding. It's very special. Yes, it's happened quickly, but Pua just lights up around Lizz. You can't fake that."

But the last word goes to the groom. Reflecting on his special day, Pua tells, "Rain or shine, it's just been so perfect. I can't believe I was gifted this in my life. People might say this has happened too fast, but when love hits you with this intensity, you don't want to spend a second apart. I know we'll be together forever."