David Hasselhoff "secretly worked out" before shooting the 'Baywatch' movie.
The 63-year-old actor is thrilled the popular 1990s TV show is making the move to the big screen, and though he was delighted to reprise his role as Mitch Buchannan, he had reservations about appearing alongside hunky younger co-stars Zac Efron and Dwayne 'The Rock' Johnson.
He told OK! magazine: "Zac is ripped but The Rock is a man and a half.
"I secretly worked out really hard because I knew I was going to have to shoot next to him. I'm old enough to be his dad."
While David was "nervous" about appearing in the movie, he ended up having a lot of "fun" with "respectful" Zac, 28 and 44-year-old Dwayne.
He said: "I had a great relationship with them and they were really cool with me.
"They wanted to know what 'Baywatch' was all about and were really respectful.
"Zac wasn't even shooting the day I was there but he came down anyway to see me.
"I was a bit nervous about going down there and they were a bit nervous about meeting me, but it turned out to be really fun."
And David thinks fans of the original series - which also starred Pamela Anderson and Carmen Electra - won't be disappointed by the movie.
He said: "I can't believe it's a movie! We filmed in Georgia and the experience was great.
"I secretly pretended I didn't like my scene but the script is actually really funny. It's exactly like the episodes.
"In the beginning we got so much heat about being a 'sexist' show but I said go to beaches in California and I'll show you lifeguards who look just like Pamela Anderson."