PETA (People for the Ethical Treatment of Animals) have sponsored the animal named Nora on behalf of the 20-year-old singer and actress to celebrate her big day and to thank her for her dedication to animal rights.

PETA Executive Vice President Tracy Reiman said, "PETA knew that sponsoring a rescued pig was the perfect birthday present for a young woman who spends so much time encouraging others to help animals.

"From promoting animal adoption to speaking up for cows who suffer on dairy farms, Miley never stops letting her millions of fans know what they can do to make the world a kinder place."

Miley is engaged to ‘The Hunger Games’ star Liam Hemsworth but recently insisted the pair are in no rush to wed as they already feel married.

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The star - who is currently working on a new album - said, "I am married in my heart and my mind. I do everything that I would be if I had the paper, but I want to take the time to actually enjoy it."

"My most important thing right now is... I want people to hear what I want to say and get my record out, so when there is a time that I can take some time off, I'll feel like I accomplished my stuff. Then I can take a break and just enjoy being married for a little while."