A boy who walked unexpectedly onto the stage to say hello to Pope Francis during the weekly Wednesday audience at the Vatican won a white papal skullcap to take home.

The boy, wearing a black tracksuit with yellow stripes, grasped a smiling Francis by the hand, before being offered a chair next to the pontiff by a senior Vatican official.

A boy makes clear he wants Pope Francis's cap during surprise appearance at Vatican audience A boy makes clear he wants Pope Francis's cap during surprise appearance at Vatican audience Photo: AFP / ANDREAS SOLARO

The child, who Francis later said suffered from unspecified learning difficulties, clapped enthusiastically.

He did not stay sitting for long, though.

Boy's surprise walk-on charms pope Boy's surprise walk-on charms pope Photo: AFPTV / Elisa COLELLA

After getting up and grasping the pope's hands again, he asked the official for Francis's cap, touching it to make it clear what he wanted.

The 84-year-old pope referenced the boy during his address, saying: "I was reminded of what Jesus said about the spontaneity and freedom of children, when this child had the freedom to approach and move as if he were at home.

Pope Francis is greeted unexpectedly by a child during the weekly general audience in the Vatican on October 20, 2021 Pope Francis is greeted unexpectedly by a child during the weekly general audience in the Vatican on October 20, 2021 Photo: AFP / ANDREAS SOLARO

"And Jesus tells us if you don't make yourselves like children, you will not enter the Kingdom of Heaven."

He told the crowd in the Paul VI hall inside the Vatican: "Have the courage to approach the Lord. I thank this child for the lesson he taught us all.

"And may the Lord help him in his limitation, in his growth, because he has acted from the heart."

It was not the first time the head of the Roman Catholic Church has been upstaged during the audience.

In 2018 a mute child from the pope's native Argentina climbed onto the stage and rolled around the floor, before taking a keen interest in a colourfully-dressed Swiss guard.