Like any parent knows, becoming a mother or father is life-altering. But the arrival of Cailin Russo in 1993 also drastically transformed her father’s music career too.

When Cailin was four years old Russo wrote his daughter a love song, which he never intended to be recorded by his skate punk band, Unwritten Law.

At the insistence of the band’s A&R, who were desperate for a single for their self-titled third album, Russo road-tested Cailin. 

“I played them Cailin which I said ‘I’d written it for my daughter and it’s a pop song and it’s not fit for Unwritten Law’ and they said ‘that song is going on the record’,” Russo reflects 20 years later.

“Sure enough we put it on the record and thank god we did because it became our first top-20 single in the United States.

“So if I didn’t have Cailin I wouldn’t have written that song, and if I hadn’t have written that song I mightn’t have a career at this moment.”

Cailin Russo is now aged 24 and famous in her own right as a model who appeared in two Justin Bieber videos.

Has Cailin and it’s very un-punk lyrics, “Hey little girl look what you do oh I love you/Hey little girl I love you” changed in meaning now his daughter has grown up?

“Not even a little bit. Cailin will always be my baby girl,” Russo says.

Songs like Cailin and Lonesome will be dusted off when the Californian punks return to Australia to celebrate the 20-year anniversary of their breakthrough 1998 self-titled record, known as the Black Album.

“The Black record I consider to be my first real record with Unwritten Law,” Russo says. “On Blue Room and Oz Factor we weren’t musicians, we were skate punks. With the Black record we worked with a couple of good producers and learnt our craft.

“It was like ‘shit, this is how to do this’. We figured out how to write songs. For me it all began with the Black record.”

However, looking back at the songs like the bleak Teenage Suicide or pubescent Sorry, Russo admits he doesn’t recognise that person.

“I was probably not the most admirable human,” he says. “I was a punk rocker, and particularly at that time, we really wanted to make music we wanted to hear. It wasn’t for anything else or for punk-rock fashion or for anything.

“We wanted to make shit we enjoyed hearing. I think if you look at the record it captured the exact mental state we were in. 

“You can judge people by their lyrics. I’ve had to re-learn half these lyrics. For some I can’t believe I wrote that, so I was a very different person than I am today.”

Unwritten Law return to the Small Ballroom on February 15.