Dannii Minogue broke down in tears as she opened up about her sister Kylie Minogue's cancer battle, and admitted it was music that kept her sibling "going".

The former 'Neighbours' actress was diagnosed with breast cancer in 2005 during her 'Showgirl: Greatest Hits' world tour, and Dannii has recalled visiting Kylie, 56, when she was "very unwell" and undergoing chemotherapy.

Speaking on Australian TV show 'Take 5 with Zan Rowe', she said: "My sister got sick with breast cancer in the middle of a tour.

"I remember her being carried off stage and stuff.

"When I would go and visit her when she was having chemo and very unwell, I would just jump around to music with her.

"It was music that kept us going and she was like, 'I need to finish the tour!' She's so professional.

"I was like, 'We need to keep you alive.'

"And yeah, like, we knew that was her goal. To get back and honour all of those tickets."

When Kylie was able to resume her tour, she invited Dannii onto the stage, and the 52-year-old singer has fond memories of the "unbelievable" moment.

She said: "So cut forward to her being able to get back on stage, it was the homecoming tour, she said, 'Will you jump on stage with me?' I said, 'Sure, I'd love to.'

"The joy when we came out on stage, from the audience, was unbelievable.

"You could hear the roar.

"We felt that the whole time, like getting her better, we felt their love and support was there. Waves of it."

Dannii's friend Laura was battling cancer around the same time as her sister, and while Kylie survived, her pal sadly died.

She explained: "My sister had cancer, recovered, it was a wild ride for our family. And then my friend Laura had cancer.

"She was staying with me and said she had a pain in her back - an hour later she was in the foetal position.

"She went into hospital and she never came out again. It was very hard to see her go through this."