Lewis rose to fame as a member of the girl group All Saints which she formed with Melanie Blatt in 1993.

At a party, Lewis was introduced by friends to Ben Volpeliere-Pierrot of Curiosity Killed the Cat, who took her to the Metamorphosis recording studios on All Saints Road, London, where she started doing backing vocals.

In 1997, All Saints experienced international success with BRIT Award-winning single "Never Ever", which is co-written by Lewis and topped the charts in the United Kingdom and Australia.

The single sold over 1.2 million copies in the United Kingdom, being certified double platinum by the British Phonographic Industry.

In 2004, it was reported that Lewis would release her debut solo single "Never Felt Like This Before" on 5 July, which would precede her untitled debut solo album on which she'd worked with numerous writers and producers including: Basement Jaxx, Biz Markie, K-Gee, Bacon and Quarmby and Trevor Jackson.

[6] Lewis has also appeared in several films including a role as Mel in the BAFTA and Golden Globe nominated Bend It Like Beckham (2002).

[8] She performed with All Saints on live television for the first time since reforming on the British light entertainment program Ant & Dec's Saturday Night Takeaway on 21 October 2006.

[10] In August 2012, it was reported Lewis was in the studio with original Sugababes line-up Mutya Keisha Siobhan, writing new material for their debut album.

[13] All Saints more recently released the 2018 album Testament saw the band reunite with producer William Orbit and was preceded by the singles Love Lasts Forever and After All.

Both albums were written by Lewis and a string of collaborators including Fred Ball, Invisible Men, Futurecut & many more.

In 2019, Lewis co-wrote the theme music for the Netflix original series 'Turn Up Charlie' with Idris Elba.

We pushed each other, we changed it a lot until, and when I finally listened to it I realised it was a love song to myself, about the person I’ve been for the past 25 years and where I am now.

[19] Further singles, "Kiss of Life",[20] "Good Mourning" (which featured Shola Ama and General Levy)[21][22][23] and "Got to Let Go", preceded the album.