As three members of the Russian punk band Pussy Riot appeared in a Moscow court charged with hooliganism, the Twittersphere lit up with pictures and messages of support from around the world.

Pussy Riot band members, Nadezhda Tolokonnikova, 23, Maria Alyokhina, 24, and Yekaterina Samutsevich, 29, were sentenced to two years in prison after performing a song criticizing President Vladimir Putin inside Moscow's Christ Savior Cathedral in February.

"Mother Mary please drive Putin away," the band had screamed during the offending gig, their faces covered in the neon masks which have now become synonymous with their campaign.

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Celebrity supporters including Beatle Sir Paul McCartney, actress and model Bianca Jagger and Robert Smith of The Cure, tweeted their disgust with the charges, calling for greater freedom of speech in the country.

"I hope you can stay strong and believe that I, and many others like me who believe in free speech will do everything in our power to support you and the idea of artistic freedom," Paul McCartney posted on Twitter.

Actress Mischa Barton tweeted: "I can't believe sentencing #pussyriot to2 yrs in jail.as someone who lived in Moscow and has filmed& seen inside the jails my heart goes out."

While the young women awaited their fate in Moscow, balaclava-clad campaigners gathered outside Russian embassies across Europe and the U.S., sharing their photos across social media.

"#PussyRiot supporters outside London embassy shout 'Shame' and 'Putin scum' as they hear of guilty verdict," Moscow news channel RT London Bureau tweeted.

Amnesty UK urged its Twitter followers to join the demonstrations, posting: "2 years in jail. #PussyRiot sentence is a bitter blow for freedom of expression in Russia."