Michael Pena had a chance to show off his hometown when he and his “CHIPS” co-star Dax Shepard came to Chicago to promote the film. Unfortunately, “I was a bad host,” said a sheepish Pena. “We really didn’t have much time …”

But Shepard came to his defense. “It wasn’t his fault,” said Shepard. “He had family duty while here. He was entertaining like 10 family members yesterday. So he’s excused.”

The funny part for Pena was how he had to deprive himself of some favorite Chicago treats. “I’m on like a crazy diet that allows me to eat 1,000 calories a day. It’s both for my role in [upcoming film] ‘Extinction’ — and because my doctor recently strongly hinted that I needed to lose a little weight,” Pena said with a chuckle.

“So, if you can imagine, I did go to Giordano’s yesterday, and I had like half a skinless chicken breast! Everyone with me said, ‘What are you doing!’ This is Giordano’s!’ ”

Riding a motorcycle as a California Highway Patrol officer came naturally for Shepard, known as a huge lover of all things automotive. As for the co-star taking over from Erik Estrada as Frank “Ponch” Poncherello in the big-screen take on the 1977-83 TV show, Pena admitted, “To be honest I didn’t really grow up with that kind of passion that Dax has. But it was something that did intrigue me. … I came to love watching motocross on TV when I was a kid, but where I grew up in Chicago that seemed like a distant dream.

“I never, ever would have thought that not only would I be re-creating one of my favorite TV characters, but that I’d get to have so much fun on a bike in a movie about those guys!”

The actor said that in recent years, he has come to own his own motorcycle and “I really love to go up and back to my golf course from my house in L.A. … The way I go takes me up and down a pretty vacant highway. I can really open it up. It’s like a dream.”

As for Shepard, the opportunity to write a screenplay — and then star in and direct this R-rated, updated version of the vintage TV show — was long on his wish list.

“Listen. My all-time hero is [writer and director] Hal Needham. All I ever wanted to do was remake [his] ‘Hooper’ or ‘Smokey and the Bandit.’ Making ‘CHIPS’ is right up there for me. … All I’m ever trying to do is to find a vehicle that will include both action and comedy — with motor sports thrown into it.

“So, we’re running around Southern California, with two odd characters being paired. It made it perfect right out of the gate,” said Shepard.

An added plus for Shepard was getting to have some fun with his wife, actress Kristen Bell, who plays his unbearable ex-wife in “CHIPS.”

“It was fun to see her as a dirtbag. She’s not cast as a jerk very often. So, it was up to me to do that,” he said, leading Pena to laugh very loudly. While Shepard had other actresses in mind for that role “who we might think of as being more believable in that vein,” Bell demanded he cast her once she read his finished script.

“I had no choice in that,” added Shepard. “She was really insistent!”