Billionaire entrepreneur Elon Musk stirred speculation this week by suggesting that aliens could currently be among us.

During a town hall event in Pennsylvania, the Tesla chief executive responded to frequent inquiries about extraterrestrial life with a lighthearted remark, saying they might be “here right now,” but added, “I haven’t seen any.”

He joked that any potential alien visitors might be so subtle that an “alien registration card” could be necessary.

Mr. Musk, who has a close relationship with space exploration through his company SpaceX, highlighted the potential for humans to become “the aliens exploring other galaxies.”

SpaceX has been collaborating with NASA and recently returned astronauts from the International Space Station. The collaborations could provide Mr. Musk with additional perspectives on the possibilities of extraterrestrial existence.

Despite his musings, Mr. Musk expressed skepticism about extraterrestrials earlier this year. At the Milken Institute Global Conference in May, he dismissed the idea of aliens visiting Earth, pointing out that his Starlink satellites have never had to evade a UFO.

Mr. Musk also noted, “For some reason, a lot of the same people who think there are aliens among us don’t think we went to the moon, which, I’m like: ‘Think about that for a second.'”

In addition to his thoughts on aliens, Mr. Musk has been actively involved in political activities, supporting President Trump’s campaign.

Speaking at an unofficial event organized by America PAC, Mr. Musk’s comments aimed to rally support for Trump in Pennsylvania, a key swing state. The event included Mr. Musk performing star jumps and leading chants of “USA” to energize attendees.