US manufacturer Watson Pharmaceuticals is changing its name to Actavis, following the acquisition of the generics manufacturer in a £3.45 billion (€4.25bn) deal.

The acquisition announced yesterday will make Watson the third largest global generics company, with an anticipated revenue of more than £5bn ($8bn) in 2012, the US manufacturer said.

The name change will come into effect in 2013, as part of a multi-year rebranding campaign.

Watson announced a "definitive agreement" to acquire Actavis in April, but the deal was not completed until this week, when Watson CEO and president Paul Bisaro said it was uniting "two powerful, profitable and rapidly growing companies into one exceptional global business".

The combined company will be the fastest-growing generic pharmaceutical company in western Europe, with operations in more than 60 countries worldwide.

"I am confident that working together, the 17,000 people of our new company will now be focused on the seamless integration of the company for strong and sustainable growth," Mr Bisaro added.