Most people see veteran actors Henry Winkler, 71, and William Shatner, 86, as celebrities, but to comedian Jeff Dye, they are "just guys".
That is because he has spent a month travelling through Asia with them to film reality TV series Better Late Than Never, and has seen them get up to all sorts of antics.
Also part of the travelling group are former American football star Terry Bradshaw and former boxing champion George Foreman, both 68.
Dye, 34, says: "If someone said something about William Shatner a year ago, I would just sit back and listen.
"Now, I would be incapable of not chiming in because I know all of these guys. I don't see them as big stars. I see them more like mentors or grandfathers. They're just, you know, guys."
Better Late Than Never is the American version of South Korea's popular show Grandpas Over Flowers, which features a group of senior celebrities travelling together without the luxuries they are accustomed to.
Dye joins them and sometimes helps out with his knowledge of technology, such as using language translator apps on his smartphone.
Despite the group's apparent chemistry on the show, none of them were friends beforehand.
Dye, who started out as a stand-up comic, says: "Henry and William have met before, but they weren't friends. The rest of us hadn't even met until the show.
"But we all clicked right away and had as much fun as anyone could have possibly hoped."
Over four episodes, the group is seen making its way through Japan, Hong Kong, South Korea and Thailand. From trying out yakitori (skewered) offal in Tokyo to filming a music video with K-pop girl group Girls' Generation in Seoul, this was one trip that "constantly surprised us", says Dye.
Besides Foreman, who had visited Japan in the 1970s, the rest had not been to Asia before.
"Every single second of every day, we were doing things and discovering things that surprised us. We would even just land at an airport and be like, 'Oh wow, check this out.' We were like excited children wandering into a new place all the time."
Dye says the show is completely real. "Maybe we had plans on certain days to go to certain places, but no one ever told us to say anything. In fact, in the beginning, William Shatner would stand around and be like, 'What am I supposed to do?'
"He is so used to acting that he forgot he can just be himself."
The show has been renewed for a second season with the same group of travellers, but the destinations are not confirmed yet.
Going by how Season 1 panned out, Dye already has some inkling to what the guys will be like in the new episodes.
"If we are measuring them by maturity, then Terry is the youngest. He is playful and silly, and if you sit down with him for dinner, you will not be having deep philosophical conversations with him.
"But we would have those kinds of conversations with Bill (Shatner). He's the most serious old guy of the lot, if you will."
He has also taken away something from being with the group.
"They're all such different personalities, but what they have in common is that they are all honourable and respectful of other people. I would want to be like all of them when I 'grow up'."