On Michael Bolton’s latest Motown-infused record, he attempts to recreate Marvin Gaye and Tammi Terrell’s chemistry on his own version of “Ain’t No Mountain High Enough” with Kelly Rowland. But admitted to Radio.com it was no easy feat to reinvent their attraction.

“You really believe these two are madly in love,” he said, noting not only how great they looked standing side by side, but also the blend of their voices.

The legendary musical couple was reportedly never together in real life, something Bolton, as a fan, can’t help but question. “It’s funny just…watching the DVDs of their performances, I don’t know,” he said. “I tend to not believe at least half of what I read, but you could flip a coin, it could be true, it could not. The important thing as artists, the chemistry was undeniable.”

As, Bolton noted, there’s only one Marvin Gaye, but he thinks music fans shouldn’t disregard Tammi Terrell’s talent. With a bat of her long lashed doe eyes and a sway of her hips, she always seemed to have Gaye under her spell. But she was much more than a cute girl with a great voice.

“She was never embraced anywhere near the level of Marvin as an artist, but she was great, not good, she was great,” Bolton said. “She’s singing like the girl next door. You really believe that these two are just madly in love with each other but then when you listen really closely, she gets really gritty and really strong and real. She’s a true artist.”

Even though Gaye had performed with many talented women — Diana Ross, Kim Weston and Mary Wells—there was something about Terrell that just clicked. The two recorded over 50 duets together from 1965-1969 including “You’re All I Need To Get By” and “Ain’t Nothing Like The Real Thing” before Terrell’s tragic death at the age of 24 from brain cancer.

“From what I understand from anyone that I’ve spoken to about it, Marvin didn’t tour for quite some time afterwards,” Bolton said.

In Ben Edmonds’ book, Marvin Gaye: What’s Going On and the Last Days of the Motown Sound, Gaye is quoted as saying, “It was a deep vibe … as though she was dying for everyone who couldn’t find love.” Her death, combined with his brother’s accounts of the Vietnam War, later set the tone for Gaye’s 1971 album, What’s Going On. But nearly five decades later, Bolton says it’s those duets with Terrell that prove how good Gaye really was.

“I watch with joy, you know,” Bolton said. “I watch and I go, they’re just making this seem so effortless.”

Additional reporting by Brian Ives