McGibbon confirmed to PRWeek he was leaving IHG, the world's largest hotel company, but declined to comment on suggestions he was set to take up a senior comms post at GSK.
PRWeek understands Joyce Lorigan, McGibbon's second in command and VP of global comms, is in talks with the hotel firm to replace him. Lorigan joined IHG in June 2010 from Golley Slater where she was chief executive of PR.
McGibbon joined IHG from Hilton International as director of external comms in 2004 before leaving to set up Parkhill Communications. He rejoined the hotel firm in 2006.