They gave themselves a deadline of a week or so to see if they could write some songs together. Because although Anika Moa, Boh Runga and Hollie Smith are good friends and among New Zealand's best songwriters, they are very different musicians with three distinct voices.
"There definitely was a question mark about how we would work together," remembers Moa of their first songwriting meeting a few months ago.
"And we decided if we weren't feeling it after one or two weeks we'd kill it," says Smith. "But after about two hours, we were like, 'Actually, this is going to be fine'."
"And now," continues Moa, "it feels weird when we're not working together."
As well as writing new music together - Be Mine, their debut single, which is out now and is the first offering from an album due early next year - the trio are also off on the Classic Hits Acoustic Church Tour for 13 shows in 11 cities during October.
It's clear they get along well. "We found out a lot of weird stuff about each other doing this," offers Moa.
"I found out that you're gay," says Smith.
"And now we're going out together," jokes Moa.
But they're a little more serious when it comes to the music-making, which they did at Runga's house from Monday to Friday writing songs for six or seven hours every day.
Runga: "Hollie lived just up the road and Anika would come in [from Titirangi] around 11am."
Smith: "And then about an hour later we'd be like, 'Have you got any wine?' It was great and we got to know each other a hell of a lot better in a short amount of time."
This year's church tour will be different from previous outings by artists such as Bic Runga, Dave Dobbyn, and the joint Boh Runga and Greg Johnson shows from 2009, because as well as performing their own songs they will also be playing new material as Anika, Boh & Hollie.
"There's never really been a girl band thing in New Zealand like this before," says Runga.
"Oh, TrueBliss," pipes up Smith.
"True. True," says Runga.
"When the Cat's Away, but they did covers," adds TimeOut.
"And When the Cat's Been Spayed," says Moa, "but that's about it. We're pretty much the new generation."
So, let's hear more about what to expect when these three women hit the churches ...
Have you been practising minding your language before the church tour [Moa is famous for her potty mouth]? And will there be a swear jar backstage?
Anika Moa: We will have a swear jar. We'll get it all out before we go on stage. I won't be able to say shit, f**** ... That's my banter. I won't be able to say anything. You can't swear in a church.
Boh Runga: I've done the church before [in 2009 with Greg Johnson] and we'll be respectful, but still have fun.
AM: So how do you do it, Boh?
BR: You just have fun. You sing. And enjoy the ambience. A lot of the churches are just incredibly beautiful and the acoustics are beautiful.
When was the last time you went to church?
AM: St Matthew's in the City for my friend's wedding. And I was raised Catholic and I used to go to church every Sunday and I quite liked it but then I got kicked out when we started doing Bible studies and my brother and I were just too hyper.
Hollie Smith: We had that thing at school where someone would come in and teach us Bible studies. But if you weren't allowed to go you had to have a signed note and then you could go and sit in the library. I was the only one in my class who wasn't allowed to go but I said to the teacher, 'I really want to stay and learn about God'. Then I asked really intelligent questions that she didn't know how to answer. She'd say, 'You just have to trust in God'. But that's not a proper answer.
Are there any of your songs that you don't think would be appropriate for the church?
HS: A lot of mine wouldn't be.
AM: Why? Do you talk about how God sucks or something?
HS: No ...
AM: And it's not like it's [the crowd] a congregation or something.
HS: But it's a spiritual place regardless of what religion you are and the politics of it all. Churches are spiritual places.
AM: Churches are like a monk's recording studio. They dream up a place to worship God in those churches and back in the day it took 50 years to build a church, to build their recording studio. So it's a beautiful place to have a concert, especially with our voices because we do lots and lots of harmonies. It's like what you said [pointing to Runga], "It's a really really little choir".
How do you complement each other, both musically and as people, do you think?
BR: We have different ways of approaching songwriting. Anika and I tried working together a few years ago but we just sat there and ended up having a beer instead. But it's better now.
AM: I have very rarely written with people and I get bored really easily. Not because the people are boring but because my brain goes tick tock.
HS: And for me, the kind of stuff I've done, is working with a producer and writing my vocals over a bed [of sound]. This is the first time I've collaborated writing proper things. And it's good because we've all got specific strengths that come together really well. Like Boh, with lyrics, if we're struggling she's really good at just putting something down and then vibing off that. And because we're all multi-instrumentalists, we swap instruments and mess around and that sparks different musical ideas.
So what have you learned from doing this project?
AM: I've learned to have patience when you're writing a song instead of just letting it go [if it's not working] which is what I usually do.
HS: When I've written I've always waited for the inspiration to come to me, especially lyrically. I can have a whole album of songs but nothing with lyrics and then after a while it starts to come. But having that discipline of writing all the time [as the trio have been doing in recent months] your mind starts working musically again, and it does become almost like a skill and one that you get better at.
BR: And another thing I realised is that we've actually worked really hard on it. It's been really hard work. I've enjoyed it.
HS: It's the hardest I've worked in ages.
And with that, they all break down into fits of laughter.
Who: Anika Moa, Boh Runga & Hollie Smith: Together in concert
What: The Classic Hits Acoustic Church Tour 2012
New single: Be Mine by Anika, Boh & Hollie, out now.
Tour dates: St John's Cathedral, Napier, Oct 4; All Saints Anglican Church, Palmerston North, Oct 5; Old St Pauls, Wellington, Oct 6 & 7; St Andrew's on Liardet, New Plymouth, October 10; Chapel of Christ The King, Hamilton, Oct 11; Holy Trinity Cathedral, Auckland, Oct 12; Holy Trinity, Tauranga, Oct 13; Civic Theatre, Rotorua, Oct 14.