Actor Ethan Hawke has delivered a strong message for Pope Francis during his appearance on The Late Show, with Stephen Colbert.

Hawke, who is an Episcopalian Christian, told Colbert about his plans to write to the Pope and ask him to lead a march to Ukraine, to bring peace amidst the ongoing Russian invasion.

The actor pointed out that the pontiff's namesake, Saint Francis of Assisi, marched to Egypt to meet with Sultan Al-Kamil in an attempt to put an end to the conflict of the Fifth Crusade.

Hawke said: "Pope Francis should take his namesake, and if he would do it, if he would lead a march from Belarus to Mariupol, and we would all go and we could bring the refugees to their homes.

"And, like, priests and rabbis, and we could all go and say you have to stop killing children.

"The choice shouldn't be whether to escalate the war, or for democracy to fail."

"I feel like the grown-ups of the world need to stand up and say, 'You're not allowed to bomb and kill children. You're not allowed to do it. You gotta behave like a grown up.'

Although the Pontiff has previously referred to the conflict in Ukraine as "cruel and senseless" he has recently drawn criticism for saying that Russia's invasion of Ukraine may have been "in some way provoked."