The six year old and his sister Shiloh, eight, acted as ring bearers at their parents nuptials in France last month, and the youngster was so determined to get his role spot on that he made sure he did everything he could to be prepared.
Speaking to UK's HELLO! magazine, in conjunction with PEOPLE magazine in the US, the couple said: ''Knox practised carrying coins and acorns on his little pillow before he got the ring.
''They picked their clothes and their duties. They all took it very seriously.''
Brad, 50, and Angelina's other children, Maddox, 13, Pax, 10, Zahara, nine, and Knox's six-year-old twin Vivienne, also had big parts to play in the couple's nuptials and the pair admitted their kids are delighted they are finally man and wife after nine years together.
They added: ''It's a wonderful feeling to be married. The children are so happy.''
The Jolie-Pitt children played a big part in designing the 39-year-old brunette's gorgeous wedding gown, which featured the kids' drawings on a fetching hand-printed veil, and the 'Maleficent' actress admits she was keen for the youngsters to add a personal touch to her attire.
She explained: ''I wanted the kids to be a part of everything including the dress because that's our family.
''That represents the way we live our life together.''
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