When Today Extra co-host David Campbell steps onto the stage at Melbourne’s Sidney Myer Music Bowl, to host – for the 12th year in a row – Vision Australia’s Carols By Candlelight concert, there are two people very dear to him who he hopes will be watching from home. One is his dad, Jimmy Barnes, who has been ordered by Campbell, his sister Mahalia Barnes, and Barnes’ wife, Jane, to “relax”, after a hectic year of touring amid health troubles. The other is Campbell’s friend, bridesmaid at his wedding, and godmother to his 10-year-old daughter, Betty, Magda Szubanski.

“Magda is really receiving everyone’s goodwill,” says Campbell, who met the comedy legend while they were performing in the Melbourne Theatre Company’s 2006 production of The 25th Annual Putnam County Spelling Bee, where Szubanski introduced Campbell to his wife, Lisa.

“I think that’s the thing that’s been keeping her going. Certainly, she’s been getting it from our family, but also from the nation.”

When Szubanski announced in July she was undergoing chemotherapy for lymphoma, the Campbells took an honest approach in telling their children.

“Betty’s nearly 11. I think that if she was much younger, it’d be much harder,” he says. “But what we just said was what Magda told everybody: She’s not well, but she is surrounded by the most incredible doctors, particularly in Melbourne.”

This year’s Carols line-up is soothingly familiar: Marina Prior, Silvie Paladino, Denis Walter, Casey Donovan, Rob Mills and the cast of the current hot musical theatre ticket in town: MJ the Musical.

“These are the sorts of things that people expect from Carols. It’s their own traditions, it’s their own favourites and I think we’d be unlucky if we didn’t supply that. I don’t want to jinx Christmas!”

Campbell will again be joined by Today co-host Sarah Abo, who was whisked to hospital last year with appendicitis before the concert.

“I was so lonely last year! We had to rewrite the whole show on the day, and luckily people like Casey and Rob stepped up,” Campbell says. “But to walk out by yourself on Carols was the weirdest feeling. I felt like Ray Martin back in the day.”

He credits his decorated musical theatre career (his trophy room includes three Helpmann Awards), with his ability to think on his feet. An ADHD diagnosis last year has also made sense of his need for diversity in his work, which takes him from the Today Extra news desk, to live theatre, to the recording studio where he makes compilation albums.

“For me, [the diagnosis] has helped really calm my mind, to work out that the issues I was creating for myself were because my brain was too chaotic,” he says. “And sometimes, in a good way. Sometimes, there’s a superpower and sometimes you’re getting in your own way. Therapy has allowed me to have a bit more emotional distance and forgive a lot of stuff, which is really handy as you get older.”

In keeping with his own Carols tradition, Campbell will perform on the night.

“I am going to sing this year. We’re still locking down what that’s going to be, but it’s really something very different for me,” he says. “I’ve been thrown a challenge. So if the challenge is pulled off, I’ve never done anything like this on stage before, so we’ll have to wait and see.”

The latest string to Campbell’s bow is a podcast he records with wife Lisa called Into the Austenverse, to mark the 250th birthday of Jane Austen. “More men should read Jane Austen, because she allows men to see how women think and act and deal with things. She can get men to teach themselves how to be better men.”

A special guest joined them on the podcast earlier this month to discuss Mary Shelley’s Frankenstein. “Magda came in and she was very funny and she seemed to have really good spirits and she’s getting her energy back. It’s been a big year.”