Here's how 'Sharknado 3' packed in all those celebrity cameos

The "Sharknado" movies have not just become a guilty pleasure because of the insane things that happen in them, but also the countless celebrity cameos.

"Sharknado 3: Oh Hell No!" is no exception with the likes of Mark Cuban, Ann Coulter, Chris Jericho, Jerry Springer, and Chris Kirkpatrick (to just name a few) popping up. But according to the screenwriter of the franchise, Thunder Levin, getting celebrities to agree to make cameos can be a challenge.

"Most of the time we don't know who is going to be in it until well into the process," Levin told Business Insider.

In fact, before production begins Levin writes a bunch of characters with one scene roles in the hopes to give them to the famous people signed on to most likely be killed by a flying shark. However, it's not often those roles get used.

"I usually get notices that so-and-so needs a part created," said Levin. "I'll say, 'We have a bunch of parts written already,' and I'm told, 'We have to create something special.'"

In some cases he'll get word that they need a role written for a cameo a few days ahead of the celebrity's shoot date. That was the case with famous illusionists Penn & Teller in "Sharknado 3," who play retired astronauts. That gave Levin enough time to write up a joke they tell about Buzz Aldrin.

Then Levin said there's the instance where he doesn't find out about the cameo until the morning of shooting.

Levin recalls a day shooting "Sharknado 3" when they had two actors scheduled to play the same part. Tim Russ and Lorenzo Lamas had been cast for the role of a general.

"We split that role into two parts," said Levin.

But the only way for it to work was for Levin to quickly write some added dialogue. With the day's shoot at a secluded location, Levin had no computer or writing area to do his magic, so he had to get creative.

"The sun was going down and we had a lot more shots to get, we needed to get it done," Levin recalls. "My dog was on set that day because we had used him in an earlier scene, so I borrowed some paper and a pen, brought over my dog and literally started writing the dialogue on my dog's back using him as a desk."

"That's the kind of things we have to do on 'Sharknado,'" Levin said.