The Spanish agency's Madrid office picked up the UK business following a final shoot-out against Adam & Eve/DDB. Both agencies are on Unilever's agency roster.
Lola MullenLowe already works on global campaigns for Unilever brands Magnum, Cornetto, and Paddle Pop.
It has now been tasked with rejuvenating the PG Tips brand, with new work expected to launch later this year.
Unilever put the business up for review in November. It moves from Mother, which subsequently withdrew from the pitch.
Mother was responsible for creating PG Tips’ long-running campaign featuring Monkey, a character that was originally created to promote the ill-fated ITV Digital.
PG Tips is the biggest selling tea brand in the UK.
Unilever has been cutting its spend with agencies over the past year, having cut fees by 17% in the first half of the year.
The FMCG giant is trying to save €2bn (£1.76bn) in its brand and marketing spend by 2019.
Unilever was unable to immediately respond to a request for comment.