For Ronan Keating, of Boyzone, joining the cast of the award-winning musical Once is a reversal. He has to sing down to the part, become a humble Irish busker. And he does this with modest grace. If there is a slight woodenness to the acting, that seems passably plausible for the shy Hoover repair man he plays. Where Keating triumphs is in the singing, giving his all to every bittersweet note of this simple and charming musical that is, thanks to Enda Walsh’s full-bodied book, even more enjoyable than the beguiling film that inspired it.

• Once is at the Phoenix theatre, London WC2 until 21 Mar