US actor John Goodman and Australian-born David Wenham have joined the cast of Soenke Wortmann's adaptation of Donna W. Cross' bestselling novel Pope Joan, which begins principal photography in Germany's Saxony-Anhalt next week.

Goodman will play the part of Pope Sergius - the role he had also been expected to play when Volker Schloendorff was previously attached as director to the Constantin Film production - while the talented newcomer Wenham, who has just finished production on Michael Mann's Public Enemies for Universal, is cast as the Knight Gerold, the love of Joan's life.

Cross' bestseller tells the story of Johanna von Ingelheim (Johanna Wokalek)who succeeded in entering the highest ranks of the Roman clergy disguised as a man and was elected Pope in 853 - a story that the Vatican claims is a myth. The book spent months on the bestseller lists when it appeard in Germany in 1996 and has since sold more than 4m copies.

The adaptation of Pope Joan - known as Die Paepstin in Germany - has been written by Wortmann with Heinrich Hadding who served as a casting dire ctor and actor on the director's 2003 football drama The Miracle of Bern.

Martin Moszkowicz and Oliver Berben will be producing for Constantin in association with UFA Filmproduktion, Medusa Films, Ikiru Films and public broadcaster ARD, with backing from Filmstiftung NRW, MDM Mitteldeutsche Medienfoerderung, FFF Bayern, and the German Federal Film Board (FFA).

Apart from Saxony-Anhalt, which recently hosted Michael Hoffman's The Last Station with Helen Mirren and James McAvoy, shooting on the English-language production will also be done at locations and interiors in North Rhine-Westphalia and Morocco.

International sales on Pope Joan are being handled by Summit Entertainment.