Maybe the only thing Paul Walker loved more than cars was the ocean.

The actor was always a huge marine biology enthusiast, having studied it in college, and was reportedly fascinated by sharks. Walker even helped with a 2013 Shark Week special "Spawn of Jaws."

It turns out that the star was actually in the middle of filming a followup to that special, called "Spawn of Jaws: The Birth," which airs tonight (August 13) on Discovery. Walker's partner on the endeavor, Dr. Michael Domeier, was very conflicted about finishing the project without his friend and colleague.

"Honestly, I really didn’t want to keep working on the film," Domeier said to EW. "But after a few months went by, I decided, ‘Okay, Paul would want us to finish it, let’s finish it.'"

Domeier said that he hadn't wanted Walker on the initial mission for 2010's "Shark Men," but that he was impressed by the actor and the two became fast friends. A couple of times, Walker even told Domeier that he wanted to quit acting and go back to school.

"He would call me in the middle of the night and say, 'Hey, I want to quit acting. I want to go back to school. Can you help me?'" Domeier said. "And I’d talk him off the ledge and go, 'Paul, that’s a really bad idea...You can have much more of an influence on these topics as a celebrity. Let’s work together. I can help you, give you talking points.'”

If the video below is any indication, Walker would've been right at home as a marine scientist. Not only does he look very comfortable with all the fancy equipment, he also got to look like a real action hero by jet skiing across the water. It's a real life "Into the Blue."

Walker's "Fast and the Furious" costar Dwayne "The Rock" Johnson filmed his own introduction to "Spawn of Jaws: The Birth," paying tribute to his fallen friend.

"Spawn of Jaws: The Birth" airs tonight (August 13) at 10 p.m. ET on Discovery.