You really must ...

check out ... the Katz eye. Monumental portraits and landscapes made the American painter's name but Alex Katz: 25 Years of Painting is the first major exhibition in the UK for one of the US's leading post-war artists. To 12 April, Saatchi Gallery, 98a Boundary Road, London NW8, 0171-624 8299

catch up with ... Jan van Eyck, one of the best-known and popular artists of the 15th-century. Building on the three portraits it already has, the National Gallery has been lent further of the artist's works by the Philadelphia Museum of Art and Galleria Sabauda, Turin. To 15 March, National Gallery, Trafalgar Square, London WC2, 0171-839 3321