The division will concentrate initially on premium travel brands but will broaden out in the long term.
Perowne joins the agency from the travel and hotel PR sector and has six years' experience. She will work with Paul Charles, who is set to join as chief operating officer from Virgin Atlantic in the new year.
Lewis founder and CEO, Chris Lewis, said: 'The Lewis heritage has, for 15 years, been in the IT sector, but we now intend to grow further through a new consumer-focused team. I am convinced that Julia will help us to transform our offering and we're delighted that she's joining our team.'