The actor returned to his hometown of Cardiff on Saturday (15Jun13) to officially open Tafwyl in the grounds of Cardiff Castle. The free event features music, dancing, sport and literature, and draws thousands of revellers every year.
Rhys heaped praise on the organisers' efforts to promote the Welsh language, despite recent budget cuts made to the week-long event.
He tells WalesOnline, "It's amazing to see how far it's come in the last eight years. It's such an important festival, not only just to promote the Welsh language but also to break down barriers between Welsh speakers and non-Welsh speakers. I honestly think it'll go from strength to strength from here."