Comedian Don Rickles may be 90 years old, but his tongue is still sharp as ever. When performing recently at Mohegan Sun in Connecticut, actor Tony Danza surprised him onstage with a birthday cake causing Rickles to snap, “I’m diabetic!”

Thursday night, Rickles returns to the NYCB Theatre at Westbury, where he will sit down and discuss his career with his pal Regis Philbin, whom he will playfully chastise, in “A Rickles and Regis Laughfest!”

Newsday recently spoke with Mr. Warmth about his landmark birthday, mixing it up with Robert De Niro and what keeps him going.

You recently turned 90. How did you celebrate?

I took the wife and drove her off a cliff.

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How does it feel to be 90?

When you reach 90, you know what’s coming up. You wake up and realize you are still functioning and working. When the big guy says it’s over, it’s over. But so far everything is going good. I still have the energy and the spark — people still laugh. Hopefully, I can reach 190, who knows?

How do you describe the format and style of your new show?

Regis and I will be onstage together sitting in chairs. He acts as the host and talks to me about my career and I break his chops. It’s more of a conversation piece that comes out funny. We take questions from the audience, too. People find it very entertaining.

How would you describe your chemistry?

I know him over 40 years, so we are pretty close. He’s a wonderful gentleman who is kind and giving of himself, which is unusual in this kind of work. He really gives his heart and soul to people.

People like getting ripped on by you. Why do you think that is?

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Because I’m not hateful or out to harm anyone. It’s not mean-spirited at all. It’s just fun and that’s why they laugh.

What do you make of David Letterman’s new long, white beard?

Well, that’s David. Maybe he’s trying to hide out.

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What do you think of the rise of Donald Trump?

I really don’t get into politics, but I know Donald. I did a private show for him down in Florida years ago. Hopefully he turns out to be OK. We’ll see what happens. Whatever is going to be is going to be.

Was Trump good to you?

No, he got up and spat on me!

What do you cite as the highlight of your career?

Performing at President Ronald Reagan’s inauguration was the most exciting thing I did on stage. It was the highlight of my life. I adore Ronald Reagan. He asked for me, and I just got out there and did Rickles.

How do you know how far to go with people?

I just know. I always do something that I believe in and that I find funny. It’s the secret to my own success. I do whatever I think is funny that comes into my mind. I’ve been very fortunate that the audience agrees.

How do you feel about the world being so politically correct?

I really can’t comment on that because I have trouble reading the comics. David, I’ll get you in touch with a rabbi and maybe he could answer that.

What do you do for a hobby?

I used to play golf, but I can’t do that anymore. So now I have a vodka and sit on the couch.

What were you like in high school?

I was president of the school, president of the dramatic society and struggling to pass my subjects. I was the class clown who was always kidding around.

Where did that spirit come from?

My mother wasn’t a comedian, but she was a very aggressive woman. My father was a very lovable guy. I was always a wise guy without being hurtful.

You are gruff yet lovable. How do you pull that off?

It’s not something you can rehearse or practice. It just happens to be my personality. I don’t know, but maybe if you have a good doctor I’ll come over your home and he can examine me!

You have a knack for improv. How did that develop?

I graduated from the American Academy of Dramatic Arts. I always wanted to be an actor. That all comes from playing make-believe when I was a kid and ribbing my classmates.

Do people have the impression that you are mean?

People might think before they meet me, “Oh, God, he’s going to kill me!” But once they know me, they realize it’s just an act.

How did you blend with Robert De Niro while filming “Casino”?

He’s a quiet man but a hell of an actor. We had a good time together. But he talks in that mumbling voice. I said to [Martin] Scorsese, “I can’t work with this man. He thinks I’m a mute or something. He’s got to talk louder or else I quit!” I’ve always kidded with Bob, but he’s a good guy.

You have been married for over 50 years. What advice do you have for younger married men like myself?

Keep signing the checks.

What else would you like to achieve?

I’d like to retire! Let’s face it . . . maybe the Kennedy Center Honors would be the top of the mark. But I’m content where I am right now.

What keeps you going?

Money! As long as people show up and they enjoy me, I’ll be there.