"I'd chased a man across the world to Paris," says Dobson. "Lara was visiting. And we met up for a hot chocolate or something in the day and she had a book under her arm of 20th century French songs that she'd bought. And we talked about the book and realised that we could both speak French, because this had never really come up before."

Known for her role in string quartet FourPlay, Goodridge had also been the head of Dobson's record label, Craving Records, which released her 2007 debut solo album Rise Up.

"Cut to a few months later, I was back in Sydney and we decided to do a song together at a warehouse party that her boyfriend was throwing," Dobson says. "We arranged a song with an accordionist that we'd found, stood on milk crates at this party and sang in harmony in French."

The performance set the mood for plenty more to come. "To sing in harmony is a great love for most singers. But to sing with somebody that you adore, in a language like French that is just so delicious. I just had this overwhelming feeling of, 'Ahh, I love doing this. This is what I want to do when I grow up,' " Dobson says.

So "exquisitely happy" working and singing together, the pair next decided to develop a whole repertoire via email and MP3s and YouTube links, just for their own sake. "Every time I'd go for a walk in the morning I had French songs in my head that I was learning," says Dobson. "And we did a show in Sydney. We didn't know anyone would come and we booked one show and a bunch of musicians, and we were hooked."

This first proper show sold out. And now, two albums and countless other sold out performances later, Baby et Lulu just haven't stopped. They were even nominated for an ARIA in 2015, for their second album Album Deux.

"People just keep coming back and they bring their friends and they bring more friends next time," the former Leonardo's Bride singer says. "It seems people really love it. Who knew there were so many francophiles in Australia."

When they get together for their Baby et Lulu shows, Goodridge and Dobson really enjoy stepping into character. "We dress up. And fortunately I've been buying vintage dresses from the '50s since forever, so I've got quite a collection. And Lara does now too," says Dobson. "It's very girlie and kind of coquettish, but very playful as well. We don't take ourselves too seriously."

Their band also plays an important role in bringing the show to life. "The band is extraordinary. And part of the joy comes from that. For me anyway," Dobson says. "I'm just so confident and supported by this band, who are brilliant. So we get to be very playful and just concentrate on the singing, which for me is a nice relief."

"It's very joyous," she says, using that word again. "Even though the material isn't all up beat, it's quite passionate and moody and dramatic as well. But over all the show is really quite uplifting."

Baby et Lulu play tonight as part of the National Multicultural Festival.

Who: Baby et Lulu

Where: Harmony Stage (Stage 1) - National Multicultural Festival

When: 8pm, Friday, February 12