NCIS’ (Tuesdays, 8 pm/ET, CBS) Michael Weatherly shares how Tom Hanks changed his life, his thoughts on turning 40 and why he’s not like DiNozzo.

TV Guide: What can you say about the reports of turmoil on the set, which ended with creator Don Bellisario leaving the show?
Michael Weatherly: I stay largely outside the politics of the show. I learned two lessons on another show [Dark Angel, in which he costarred with — and became engaged to — Jessica Alba]: The less I say the better, and don’t date your costar! So Mark Harmon and I have never dated. Though the Silver Fox and I did spend a week in Vermont that nobody knows about.

Scan a list of TV’s top 10 programs and you’d expect to find the durably popular “CSI: Crime Scene Investigation.” But now it’s got unlikely company from another series with an alphabet-soup title: “NCIS.”

CBS’s drama about navy crimebusters has managed the neat trick of climbing in the ratings in its fifth season, even as many new shows and some veteran ones are finding it tough this fall to woo viewers.

EARLY in his NCIS career, Michael Weatherly detoured from his script but neglected to tell the writers, cast or crew of his plan.He put his own words into the mouth of NCIS special agent Tony DiNozzo and startled cast members sharing his scene.

“Normally when you want to change a line or use a new prop or even pick up a pen, you have to talk to a lot of people about it,” Weatherly says.

“I just started doing it. I wanted to break out of this rut I found myself in by trying to be a little less stiff.
“I gave myself permission to not ask permission of the people around me.”

You’re in Sydney for the TV Week Logie Awards and a slew of press commitments for NCIS. How’s it going?
I’m having an amazing time. The flight alone [from LA] is so much fun. I’m a fan of the plane wine. [Laughs.] So it’s been an absolutely wonderful time. Hamish and Andy — I love them. I had so much fun meeting them backstage [at the Logies] and then doing their radio show the next morning. I was exhausted, but they carried me through. And I have to say a slew of other people that night were so much fun. Fifi Box has more energy than a hurricane. It’s been extraordinary. And yesterday I had a great big walk through Sydney with my niece [Alexandra Breckenridge].