WATCH: Little girl goes viral when she steals the Pope's hat

It was the perfect crime. A viral video has shown the moment a little girl stole Pope Francis' hat.

Estella Westrick, a three-year-old from Atlanta, Georgia, was greeting the pontiff in St Peter's square in the Vatican. Pope Francis leaned toward Westrick to give her a kiss, at which point she snuck her arm around his head and whisked away his skullcap, also known as a zuchetto. The surrounding crowd immediately burst out in laughter, including Pope Francis. The moment was shared on social media and has quickly gone viral.

Estella was taken to meet the Pope following his Wednesday audience by her godfather Mountain Butorac, a Catholic tour organiser. 'Right before she went up she was a little nervous,' Butorac told CNN. 'Then she stole his hat. It was hilarious. Everyone was laughing, including the Pope.' Butorac posted on Facebook and Twitter: 'Took my Goddaughter to meet the pope! She stole his hat!' His tweet has since received 34,000 likes and 15,000 retweets. He later posted in a selfie with his goddaughter: 'We had a fun day.'

Estella is currently visiting Rome with her parents.

Butorac joked: 'It's her first full day in Rome. Who knows what she will get up to tomorrow.'