The detained Russian punk-rock female group Pussy Riot now has a new supporter in their corner, and it's a pretty powerful ally:  Beatles legend Sir Paul McCartney.

The group has spent the last five months in pre-trial detention for allegations stemming from an anti-Putin protest, and the global support surrounding the three detained members is mounting. In what was described as an unauthorized protest at Moscow’s Cathedral of Christ the Savior, three of the members were arrested and charged with hooliganism -- a charge that could carry a seven-year jail sentence.

Since their detainment, supporters around the globe have rallied to show their support and outrage over the seemingly unfair situation. Celebrities like Madonna and Sting have already come forward showing their public support for their freedom of speech, and now McCartney has posted an open letter to Nadya, Katya, and Masha on his website and social media outlets, expressing his thoughts:

Dear Nadya, Katya & Masha,

I’m writing to show my support for you at this difficult time. I would like you to know that I very much hope the Russian authorities would support the principle of free speech for all their citizens and not feel that they have to punish you for your protest. Many people in the civilized world are allowed to voice their opinions and as long as they do not hurt anyone in doing so I believe this is the best way forward for all societies. 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.

Wishing you the very best of luck,
Paul McCartney

With the judge scheduled to deliver the verdict tomorrow (Aug. 17), supporters have vowed to assemble to show their support outside the court in what many have deemed unjust claims and demand the three are set free.