The agency has recruited Damaris Anderson-Supple as COO in the UK. She will also serve as executive chair of the healthcare & wellbeing division.
She joins from Merck, previously known as Schering Plough, where she was global marketing lead.
In her previous role, Anderson-Supple was responsible for an anesthesia product launch in 30 countries and gaining regulatory approvals across Europe, Asia-Pacific and Latin America.
Millar commented: 'Damaris' sector expertise, her global perspective and first-hand experience of the changing client agenda will bring huge value to the wider agency.'
Anderson-Supple has built a long track record in the pharma and healthcare sectors, having previously led Organon UK and Ireland as MD of the 200-strong pharma firm before it became part of Schering Plough.
She said: 'The agency is at such an exciting stage in its growth and the plans that are in place will afford many new opportunities.'