Klein, who holds the position of chief marketing officer, has been with the fast food chain for six years, having joined from 7-Eleven.
The move was confirmed by BK in statement, which read: "President-Global Marketing, Strategy and Innovation Russ Klein has taken a personal leave of absence.
"During his temporary absence, senior VP-Business Intelligence Mike Kappitt will lead all marketing activities for the company."
In a separate email sent to company employees, John Chidsey, CEO of Burger King, wished Klein "a speedy return."
Klein is highly regarded within the industry and is credited with presiding over an edgy and bold creative direction, which has resulted in the popular online campaign, Subservient Chicken.