Alan Alda talks about his lifelong romance with wife, Arlene

NEW YORK, April 9 (UPI) -- While talking recently about his new big-screen romance The Longest Ride, actor Alan Alda recalled how he knew his real-life wife, Arlene, was the gal for him when they met back in the 1950s.

"Here's how we knew we'd be together forever," the 79-year-old M*A*S*H icon told reporters during a recent roundtable interview in New York.

"Pretty much the first time we met -- we had met once before, but I was too shy to even say, 'Hello.' So, the next time, we're at dinner at somebody's house. The woman who had invited us had made a rum cake for dessert, and she had it on top of the refrigerator, and the refrigerator shook while it worked and the rum cake slowly moved to the edge of the refrigerator and fell splat on the floor of the kitchen, and Arlene and I were the only two people who got up with spoons and ate it off the floor. So, that's how you know if people are going to be together. Just throw a cake on the floor and see who goes for it."

Alda plays World War II veteran Ira in his latest movie, which is an adaptation of Nicholas Sparks' bestseller. After Ira accidentally drives off a North Carolina road one rainy night, Sophia, the college student who helps rescue him, stays by his side and reads him old love letters he penned to his wife, Ruth, as he recuperates. Through flashbacks, the story of Ira and Ruth's passionate, but sometimes challenging marriage unfolds, as Sophia works out her own romance with a professional bull-rider named Luke. Jack Huston and Oona Chaplin play the young Ira and Ruth, while Britt Robertson is Sophia, and Scott Eastwood portrays Luke.

"That's what makes this movie unusual to me," Alda said, noting the story is about more than just physical attraction and chance meetings, it also depicts the reality of two people building a life together.

"Most movies stop right at the part where this one really picks up steam, which is how do you stay together for a long time?" the actor said. "And the writing really gives them obstacles that are tough obstacles. They are not just things that you can solve with a little late-night conversation. You really have to give."

Alda admitted he was excited to see what the completed film looked like, since there are essentially three different story lines and numerous scenes in which he does not appear.

"I loved it because I saw parts of it I hadn't seen when we were shooting," he explained. "I just knew the script, but I didn't know what [Chaplin and Huston] were doing with the early part of my life. And it was fun to see them mesh together like that. I had a great time seeing it. To see the bull-riding. I had no idea I'd be so involved emotionally in riding a bull. Scott was so good. Every time he got on that bull, I really felt for him."

So, how did Alda and Huston work together to create the seamless evolution of their shared character?

"We both paid attention to how the other one talked. He asked me to record some lines to see how they would come out of my mouth, and I listened to him constantly, while he was reading his scenes and at dinner, and I was making mental notes on his voice," Alda said. "So, we were each trying to copy each other's voice. ... I think we sound pretty much alike. He had the harder job."

Asked if he has any plans to retire from acting since his 80th birthday is just around the corner, Alda laughed and asked, "To do what?

"Actually, I have plenty of things to do besides acting. I write and I do the science stuff, but I love this. It's wonderful to do what you know how to do. And to get better at what you know how to do. Those are the two greatest pleasures for me."

The Longest Ride is to open in U.S. theaters Friday.