The actor/model and singer/model have rekindled their romance, eight years after they first dated, while filming a music video for the sisters' new song On Your Side, that Rose wrote, directed and stars in.

Speaking about The Orange is the New Black star on Nova's Fitzy & Wippa, Origliasso explained she always had a soft spot for the Melbourne star and they remained friends, even after their split: "It's sort of a sweet thing, love never dies."

She added: "We adore each other... We've supported each other through the last eight years of our lives, personally and professionally we've really grown together."

Appearing on KIIS 1065's Kyle and Jackie O Show on Tuesday alongside Lisa, her twin sister and bandmate, Origliasso added: "[Ruby] is such an incredible woman. I feel so proud to be with someone like her. She's so ambitious, compassionate and incredible."

Meanwhile, Lisa, who is still "loved up" with long-term partner Logan Huffman on a farm outside LA, joked that she now feels like she is "third wheeling".

The pair first ignited rumours they were back together when Rose started posting pictures with Origliasso on social media.

Rose split with fiancee Phoebe Dahl in late 2015, and model Harley Gusman in late August.