You never know what things end up coming in handy.
Co-stars Ashton Kutcher and Jon Cryer stopped by The Conan O'Brien Show
on Wednesday ahead of the Two and a Half Menseries finale
, where Cryer revealed how Kutcher immediately endeared himself to the cast and crew after replacing Charlie Sheen in 2011.
And it involves the 37-year-old That '70s Show actor busting out a huge prosthetic penis that he just happened to have in his trailer.
"In the very first episode that Ashton was in, there was a point in which he had to drop trou and be completely naked in front of me, and we didn't know how to do that in front of the live studio audience without him actually being naked because the whole point is it's supposed to shock people," he explained about the moment he knew Kutcher's casting was going to work for the show. "And people were working this over in the writers' room and Ashton pipes in, 'Oh, well, I've got a huge prosthetic penis in my trailer.' And we all had that awkward moment of, 'Of course you do ....'"
Kutcher says he had the X-rated prop because he was producing web shorts and hidden camera pranks at the time.
"Who knows when you're gonna need a prosthetic penis, so I kept it," he explained. "And I just happen to have it around."
And was he himself the model for the "very impressive anatomically correct member?"
"Listen, they only had one guy willing to be the mold," he joked, raising his hand.
ET actually caught up with Kutcher last December, when he addressed the speculation that Sheen would be returning for the long-running show's series finale.
"If you're working on the Warner Bros. lot and hear sirens, come save me," Kutcher joked.
Two and a Half Men's series finale airs tonight at 9 p.m. ET/PT on CBS.