During an interview with Page Six about his new book, "The Most Human: Reconciling with My Father, Leonard Nimoy," Adam Nimoy shared his insight into the two men's long-standing feud.
Newsweek emailed Shatner's publicist and Adam Nimoy for further comment on Monday.
"I know why," Adam Nimoy said about the reason for the feud, before saying he plans to "let sleeping dogs lie.
"It's unfortunate, it's sad, you know but it is what it is, you know. There's nothing we can do about it, nothing I could have done about it, and uh, and I love Bill.
"But they had a very, you know—I can say, I will say, that they had a very challenging relationship themselves. Although there was a period of time when they were really beautifully, I think, together."
Adam Nimoy went on to say that he and his sister had heard stories about the two actors arguing while on the Star Trek set, so they were shocked when Leonard Nimoy referred to his former co-star as his "best friend" in a biography.