The group emerged in 1998, when Zara Clark and Vanessa Kelly were brought together by producer, songwriter and musician Chris Banks.

Zara Clark first joined Chris Banks and producer Michael Lloyd in 1996 after responding to an advertisement for a singer to work on a demo project at the studios of radio station More FM. Eventually Clark felt the group needed another singer and Vanessa Kelly joined.

Deep Obsession signed with the newly opened local subsidiary of Universal Music and went on to release their own material.

Clark sang advertising jingles at the station, where they had the ear of the station DJs. Their debut performance was on a More FM boat cruise around Waitemata Harbour.

Deep Obsession’s demo version of Air Supply's hit ‘Lost in Love’ was picked up by radio, first by More FM, followed by competing network ZM.

“We started working at More FM studios at night-time, from midnight to about 5am some mornings, just writing and getting plans together,'' Clark told TV One's Matt McLean in 2015. “We ended up getting on the radio before we had a record deal ... That's how it really started for us.”

Deep Obsession signed with the newly opened local subsidiary of Universal Music and went on to release their own material. ‘Lost In Love’ was remixed by Malcolm Welsford and released in late 1998; with strong support at radio it went to No.1. Their original songs ‘Cold’ and ‘One And Only’ also went to No.1, the band making New Zealand music history as the first Kiwi act to achieve three consecutive No.1 hits on the official New Zealand music charts.

In 2015 that record still stands. Deep Obsession were recognised at the 40th anniversary of the New Zealand Music Charts in May 2015.

"It was like a flash in the pan. We were there one minute, gone the next." Clark told TV One. "I've never felt particularly special in any way. But that moment, I really felt like something special was really happening. Like this was not just ordinary."

Both women had a background in performance. From Whangarei, Zara Clark studied journalism for a year before turning to singing. She toured Northland with bands, playing pubs and festivals. Vanessa Kelly moved from Auckland to Christchurch, where she studied drama, singing and dance and graduated from the National Academy of Singing and Dramatic Art in in 1996. Kelly returned to Auckland and worked with several bands before joining Deep Obsession.

Founder Chris Banks was key to their success, as musician, co-writer, producer, and additional vocalist on their debut album, which was ready for release when he called it quits.

Banks wanted the act to remain a studio band while Clark and Kelly wanted the focus to be on live performance. Clark and Kelly wanted more say in the group and called a meeting at their record company, Universal. “Vanessa and I put our needs forward – that we would like to have our say and could there be more of a consensus. That wasn't really what Chris wanted to happen so he resigned,” Clark told the NZ Herald in 2000. "Some people want to be captain of their ship but that's not really the way we work."

The album Infinity was released in 1999 and went to No.8 on the Official NZ Album Chart, achieving platinum sales.

The album Infinity was released in 1999 and went to No.8 on the Official NZ Album Chart and was certified platinum – appropriate given their platinum blonde image. The album yielded two more singles: ‘You Got The Feeling’ hit No.17 and ‘I Surrender’ charted at No.25. In 2000 another version of the album was released in Japan by Universal International.

In 2000, Vanessa Kelly won a Tui for Most Promising Female New Zealand Vocalist at the NZ Music Awards. She decided to leave Deep Obsession in 2001. “It wasn't a great scenario, being totally honest.” she told the Otago Daily Times in 2015. “I think probably [there was also] the mistrust in what the record company had created as well. They said in the beginning it wasn't going to last, so they set it up to fail and that was the hard part – that we didn't have that support as a unit.”

Kelly was replaced in Deep Obsession by Sharleen “Charlie” Lawson. With Zara Clark they recorded two new tracks, including ‘Miracles’ which reached No.34 due entirely to strong radio airplay – the track was not available for sale.

For Kelly, the transition from Deep Obsession to being a solo artist was difficult, she told the ODT. “You go from this scenario where everyone thinks that you're financially loaded and you're actually broke.”

Kelly shifted around several genres and toured through New Zealand during 2005 and 2006. She moved to England for around two years and returned to New Zealand in December 2007, eventually settling in Oamaru. In 2013, she started working at the University of Otago as a contemporary music vocal coach.

“At the end of the day, it was awesome; it was so much fun,” Kelly told the ODT. “I got to live a dream – when I was a kid I wanted to be a pop star. We had an amazing time, we learned a lot together, we grew up together and now we're all off on our own journeys.”