The model-turned-singer will return to his fashion roots by signing a contract with the top modelling agency.
Siva was originally scouted to be in the chart-topping boy band - also consisting of Max George, Jay McGuiness, Tom Parker and Nathan Sykes - after music managers spotted him in modelling campaigns as a teenager.
Since joining the band in 2010, Siva has enjoyed worldwide success with hit singles including 'Glad You Came' and 'Chasing the Sun'.
The 24-year-old star will now document both his music and fashion careers in the band's new E! reality show 'The Wanted Life'.
A spokesperson for the agency told Vogue.co.uk: ''Next Model Management is delighted to announce the signing of Siva.
''Undeniably gorgeous, and with a really genuine love of fashion which stems from his history as a model, we are excited to be developing his fashion profile alongside his hugely successful career as part of band The Wanted and look forward to seeing it all unfold on his new TV show, 'The Wanted Life'.''
Other musicians signed to Next Model Management include Rita Ora, Lana Del Rey and Iggy Azalea.