The agency is best known for its business-to-business marketing support to global mobile operator Vodafone.
Perrett has been appointed to bolster 's expertise in the delivery of digital media campaigns and to reinforce the agency's commitment to new media creativity.
Perrett trained as an artist before taking his first position in the advertising and design industry.
He has been in the business for 20 years and, in that time, has created campaigns for blue-chip clients in the automotive, retail, charity and fashion industries.
Perrett will now use his expertise across a range of Mi Liberty's technology clients.
Stephen Sharp, joint managing director at Mi Liberty, said that he was impressed with Perrett's commercial awareness in addition to his creativity and design skills.
Sharp said: "I'm looking forward to working with Chris to offer our clients an array of creative new media services including YouTube-like videos, short promotional films, e-books, podcasts and Web 2.0 products."
Perrett said: "I'm passionate about the power of imagery and communications and how it can influence our lives and I'm looking forward to creatively shaping the marketing communications campaigns offered across the clients here."
Mi Liberty's global headquarters are in Chelsea, London. It also has offices in Farnborough, Paris, Barcelona, Milan and US headquarters in Atlanta.