Barnes recently left TRO where he held the same position.
He has been working in experiential and integrated marketing for more than 14 years.
Avantgarde said his planning and business development skills mean that Barnes seeks out a "deeper understanding" of clients businesses. It also describes him as its "resident geek" who has a deep knowledge of all the latest creative technical innovations.
Barnes said: "I’m really pleased to have joined Avantgarde at an exciting point in their growth both in the UK & globally.
"Most importantly for me and my passions, they continually strive to produce innovative industry leading work that pushes the boundaries of what is possible across all brand experience disciplines which makes it a very compelling story to take to market."
In February, Avantgarde recruited Lizzie Carver as its new client services director, following her departure from MCM.
Avantgarde has also launched a newly redesigned website www.avantgarde-uk.com. The redesign champions its new brand positioning and communicates the wider brand experience offering that its has been delivering for clients over the past 12 months.
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