The 32-year-old, who has made 66 international appearances, joined Spartak Moscow this month after a five-year spell with city rivals Lokomotiv.

Stiller is a long-term Goodwill ambassador for UNHCR – the UN refugee agency.

The actor said he hoped to ‘share stories that illustrate the human impact of war and to amplify calls for solidarity’.

Margaret Atwood, James Norton and Ed Harris are among the stars who have signed a letter in support of LGBT rights in Poland. In June, the country’s president Andrzej Duda promised to protect traditional Polish values against LGBT rights.

Pope Francis has continued his clear-out in Poland after revelations of clergy sexual abuse and cover-up. This has included replacing Gdansk Archbishop Slawoj Leszek Glodz on his 75th birthday.