Hundreds of people flocked to Waikiki on Thursday evening to catch a glimpse of the stars of “Hawaii Five-0” and “Magnum P.I.” during a Sunset on the Beach screening of the premiere episodes at the Queen’s Surf Beach.

“Hawaii Five-0” is beginning its 10th season and “Magnum P.I.” is entering its second season on CBS. Fans can expect significant crossovers this year, said Peter Lenkov, executive producer of both series shot in Hawaii.

“The two universes coexist,” he said. “We’ve had a lot of characters cross over. We’re going to do it more this season on both shows. We’re going to really blend them together a lot more. This year it’s going to be almost everybody.”

During its first season, local actors Kimee Balmilero, Taylor Wily and Dennis Chun, part of the main cast of “Hawaii Five-0,” appeared in several episodes of “Magnum P.I.”

Jay Hernandez, who plays Thomas Magnum, told the Honolulu Star- Advertiser that after the first season he has yet to claim the iconic role — originally played by Tom Selleck — as his own in the remake of the classic 1980s television show. Selleck starred in the original series from 1980 to 1988.

“I think I’ve won over people who were doubters initially,” he said. “I have fun playing this character. I think as time goes by there’s a generation of kids — of viewers — that for the first time are seeing ‘Magnum P.I.’ I am the only thing they associate with that. They don’t associate Tom Selleck with it, so for myself I feel like I’m defining it for a new generation and that’s exciting.”

Alex O’Loughlin, who plays Steve McGarrett on “Hawaii Five-0,” was excited about going into season 10 of the reboot of the original series that ran from 1968 to 1980.

“How many decades do we get as human beings? I mean, seven, maybe eight? It’s 10 years,” he said. “I’m kind of like in an existential crisis. I’m really grateful to be here.”

When asked what would be the perfect end to his character, O’Loughlin said, “Life’s hard and people die and then we move on. The fact that McGarrett’s still alive is kind of crazy. He’s more like a superhero than an actual, like, real hero, which is a real person. Everyone’s going to get mad at me, but I think he should die. I think he should die in a glorious way fighting for something really important because that’s what happens in real life.”

“Hawaii Five-0” and “Magnum P.I.” both will premiere Sept. 27 at 7 and 8 p.m., respectively, on KGMB. They will continue to run back to back in those Friday night time slots through the season.