The sisters shared during a 60 Minutes interview that they didn't perform together for over a year during that time that Jess and Ruby were together.
"When you have a twin, you've got back up for everything," Jessica shared. "But sometimes to evolve as an individual, and to find the love for myself I needed to find, I needed to just go through experience for myself."
When asked how she coped, Lisa said the period of time was "heartbreaking".
"I don't know if there's any words for how hard that was," she said. "It's heartbreaking. She's my best friend, so not being able to reach out and check-in, see how she's doing, or tell her what's going on with me [was hard]."
The pair admitted The Veronicas could have become a thing of the past due to the feud.
"We weren't able to create, we weren't able to perform. I mean, we couldn't be together. We had to have things on hold," Lisa said.
Luckily for fans, however, she added the music was what brought them together again.
"That's where the magic of music is truly a spiritual experience. Because that is our language we have together when words are too tough."
Working on their first studio albums in seven years - Human and Godzilla - is what fixed their relationship.
Jess and Ruby once dated in 2008, but rekindled after the actress appeared in The Veronicas' video for 'On Your Side' in 2016. They dated for two years, splitting in April 2018.
Jessica tearfully explained on their reality show The Veronicas: Blood is for Life how her "isolating" romance almost destroyed her bond with Lisa
"Lisa and I didn't talk for a year," she said. "I was in a relationship that wasn't good for me. I became isolated. I had nobody anymore, I only had my relationship."
"I didn't have my mum or my dad. When it became too much for me... I walked away," she added. "I realised I'd become the enemy in the situation. And I was ultimately... my presence and my love was making it harder for [Jess]."
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