Game Of Thrones star Iain Glen has pulled out of his role in a London play due to ill health.

The 52-year-old Scottish actor has been appearing in Fortune's Fool at the Old Vic theatre since last month (Dec13), but he was forced to take a week off after he was struck down with a mystery illness, and now he has left the cast.

Actor William Houston has stepped in to take over the role.

A statement posted on the theatre's website reads, "Unfortunately Iain Glen is unwell and has been advised by his doctor to withdraw from Fortune's Fool in order to regain his full health... Everyone at The Old Vic wish (sic) Iain a speedy recovery and thank (sic) William for stepping into the role at short notice."

Glen's actress wife Charlotte Emmerson has spoken out about her husband's health crisis, telling the London Evening Standard he is on the road to recovery, saying, "He is doing really well. He just needs time to recuperate. But he is absolutely fine and just needs time to rest."