She's had a long career in television production and set up the Raukatauri Music Therapy Centre, named for her 16-year-old daughter, for children who have disabilities.
In the flesh she's funny, sweet and a powerhouse of energy.
Diagnosed with a lump in her right breast, she was initially advised by her doctor that a lumpectomy might be enough. However, the tumour was more aggressive than first thought and spread to her milk ducts.
George Bradfield, her partner, nearly fell off his chair when she told her doctor to "lop them both off". She had spoken to other women who had had cancer and she didn't have any trouble making the decision because she didn't want to worry about it coming back in her left breast.
What followed was a seven-and-a-half-hour operation to remove her breasts and move muscle and fat from her stomach into the cavity to reconstruct them.
The decision wasn't difficult, considering her breasts - about 2kg came off when they were removed - had always given the singer, who is only 154cm tall, some trouble.
"You could always see my boobies coming around the corner before me. I suppose I could have taken offence, I have male friends who used to go, 'Hey, fat tits!' So they were out there and they were heavy and so I wasn't so concerned about losing the bulk of them.
"When George and I went to see the plastic surgeon he was a little worried about us, well me, because we were laughing and cracking up. He didn't think I appreciated the seriousness of it. For me it was like a dream come true. Let's face it, to be told you can have a reduction, reconstruction and a flat stomach - let me at it."
The flip side of good-looking breasts is that they still feel tender and numb even a year later.
But everyone wants to know about her new nipples, she jokes, which were made from her own skin, coloured by a tattoo process and then formed by another surgery, about nine months after the reconstruction proper.
A 6-year-old nephew, who caught sight of her getting changed before that operation, gave her the biggest laugh when he asked how she was going to feed her baby.
In the past year she's had her hair fall out from chemotherapy, laughed with former All Black Norm Hewitt about how to deal with razor rash, and at the same dinner shocked ex-captain Taine Randell, who didn't know she was sick, by wiggling her wig around her head.
But there have been hard times too. She tells the Weekend Herald of three close friends diagnosed with the disease in two years. One has died. She had a long painful recovery after the surgery, and there were other "howlibag" difficult moments.
But overall she's focused on being a mum to a blended whanau of six. She wants to be around for as long as she can. She's on hormone treatment that gives her a 95 per cent chance of not relapsing.
There's a big reason she's so open about her experience. Mohi wants women who are considering a double mastectomy to have practical information about the option.
"I can talk to women about real fears that they have. Every situation is different but to be able to share your story for others to give some comfort is a good thing."
She's doing it one friend at a time in her own earthy, hilarious way.
