
As client partner, Weetch will also sit on the Mindshare management board. He will be based in London and report to Nick Ashley, the chief client officer.
Weetch began his career at Mindshare in 1999 as a TV buyer on Warburtons, Mattel, Boots and Pepsi.
In 2003, he joined the then 30-strong Mindshare global team, working on WWF and Rolex. He was then named the global client leader on the HSBC account.
Weetch moved to Mindshare Sydney in 2011 to run the Kellogg’s account before joining Ikon in February 2014.
Lianne Norry, the director of brand and communication at Three, said: "At Three we are all about shaking up the mobile market and I’ve invited Alan to join us on that journey."