Billy Ray Cyrus: Not sure Miley Cyrus will marry Liam Hemsworth

Billy Ray Cyrus, country star and father of Miley Cyrus reveals he's not certain that the 20-year-old singer and her fiance, Liam Hemsworth, will end up getting hitched.

Cyrus says that he purposely didn't include too many details about his daughter's engagement to Hemsworth in his new memoir, "Hillbilly Heart" just in case it didn't work out.

"I know as I was writing the book I wanted to keep that particular moment as open-ended as possible," Bill Ray, 51, told ABC News in a new interview. "I didn't know the answer. They're young. They're kids. The great news is, they're great friends. They're really, really good friends. If you end up getting married, that's your business too, you know?"

Miley and Hemsworth, 23, became engaged in June 2012 after getting together on the set of their film, "The Last Song," in 2009. Their have been multiple rumors that their engagement has been on the rocks, but Cyrus continues to defend their relationship. However, it looks like the man who would walk her down the aisle has some doubts.

"I don't know. I really don't," he said on whether he thinks the couple will actually wed. "I play it by ear and I know whatever is meant to be, that's the way it's going to happen."

Miley has yet to comment on her father's latest remarks, but she did tweet on Sunday: "Dad and I are so in sync sometimes it's crazy. The book. Billy Ray Cyrus."

Something tells us, she may be tweeting a different tune soon.