US pharmaceutical company Actavis has agreed to an all-stock takeover of Irish rival Warner Chilcott worth $8.5 billion (6.6 billion euros), the pair announced on Monday.

"Actavis, Inc. and Warner Chilcott plc today announced they have entered into a definitive agreement under which Actavis will acquire Warner Chilcott plc in a stock-for-stock transaction valued at approximately $8.5 billion," a joint statement said.

The deal will create "a leading global specialty pharmaceutical company with approximately $11 billion in combined annual revenue" -- focused on women's health, gastroenterology, urology and dermatology, the statement added.

"We have set as our strategic corporate objective to build a leading global specialty pharmaceutical company," said Actavis chief executive Paul Bisaro.

"The combination of Actavis and Warner Chilcott creates a strong specialty brand portfolio focused in therapeutic categories with strong growth potential, and is supported by a deep pipeline of development programs," he added.