Pope Francis said in his morning Mass on Monday that if Martians came to him asking to be baptized he wouldn't turn them away, Vatican radio reports.

The pope's message was one of inclusion, saying the Holy Spirit is not always predictable. He told a story from the Acts of Apostles in which Peter observes a group of non-Christians receiving the Holy Spirit. Other Christians later criticize Peter for consorting with these people, to which Pope Francis responded:

"That was unthinkable. If – for example - tomorrow an expedition of Martians came, and some of them came to us, here... Martians, right? Green, with that long nose and big ears, just like children paint them... And one says, 'But I want to be baptized!' What would happen?"

Pope Francis would not be one to turn away someone seeking baptism -- even if they were an alien. He urges clergy to foster an open door policy for all to receive church teachings.

"Who are we to close doors? In the early Church, even today, there is the ministry of the ostiary [usher]. And what did the ostiary do? He opened the door, received the people, allowed them to pass. But it was never the ministry of the closed door, never."

Pope Francis is not the first one to hint at alien baptism. Vatican scientist Guy Consolmagno suggested in 2010 that aliens might have souls and could be baptized if they asked for it.