Brecht's play about the 17th-century scientist's flight with the church over his assertion that the earth orbits the sun will be presented in a new translation by Mark Ravenhill, the RSC's writer-in-residence, and directed by Roxana Silbert. Also in the cast is Jodie McNee, who returns to the company to play Virginia after previously playing Roxana in Silbert's production of Measure for Measure and appearing in Written on the Heart.

McDiarmid and McNee join the RSC's current acting ensemble, who will also appear in The Orphan of Xhao and Boris Gudonov with which it will run in rep.

In a press statement, Silbert commented of McDiarmid: "Ian is a brave, fearless, charismatic actor brimming with the acute intelligence demanded by the role of Galileo."

McDiarmid previously worked with the RSC on the 1976-77 and 1984-85 seasons, and was subsequently co-artistic director with Jonathan Kent of the Almeida Theatre. Recent roles include the title role of Timon of Athens for Chicago Shakespeare Theatre, and appearances in Emperor and Galilean (National Theatre) and The Prince of Homburg and John Gabriel Borkman (both Donmar Warehouse). On Broadway, he has also starred in Brian Friel's The Faith Healer. He is perhaps best known for his screen role as Supreme Chancellor Palpatine and Emperor Palpatine in George Lucas's "Star Wars" series.

To book tickets, contact the box office on 0844 800 1110 or visit www.rsc.org.uk.