And while they are known for their performances as a duo, the twins shared that this battle is one they are being forced to do apart in order to protect each other.
"So, all of a sudden, boom. In Covid, I can't be with Jools. I came out of the office at St George's Hospital and I sat in the car. I just burst into tears," Lynda shared with Sunday.
"I don't know what's harder - having cancer or not having Jools here," she added.
As well as keeping the beloved 63-year-old twins apart, Covid-19 also forced them to cancel gigs and their income took a hit, adding to the stress the pair were facing.
The pair became Kiwi television staples with their show The Topp Twins, where they played characters Camp Mother, Camp Leader, Ken and Ken.
The show then sparked a feature film, and multiple TV spin-off shows as well as hundreds of performances across the nation.
In 2018 the entertainment duo was made Dame Companions of the New Zealand Order of Merit for services to entertainment at Government House.
The pair were draped in korowai - the first Dames in New Zealand to wear them. The korowai, woven by Kiri Nathan, was a new addition to the investiture of Dames.
The Topp twins then sang a waiata, with Jools ending it with "Kia kaha, be strong".
Watch the full interview with Jools and Lynda on Sunday, TVNZ1 7.30pm or OnDemand.