The assignment is for Pizza Hut's "Insider" specialty pizza.
Pizza Hut, which spends about $150 million a year for advertising, has been with Omnicom Group's BBDO Worldwide, New York, for 15 years. The company has said BBDO will remain its primary agency.
Executives at Wieden did not return phone calls.
The win is a major boost for Wieden, which was a finalist but did not win the pitch for the $300 million General Motors Corp.'s Saturn Corp. account, and was eliminated from the review for the $160 million Hyundai Motor USA account.