"They're really happy together right now and they know if they need a preacher, they've found one," the 54-year-old said Wednesday on the Today show amid rumors that the couple's engagement is back on.
Cyrus, 23, and Hemsworth, 26, were previously engaged but split in 2013 after four years of dating. They appeared to reconcile over New Year's and Cyrus was later spotted wearing her engagement ring.
"I guess when I feel something, then I just feel it and I go for it," Hemsworth explained in the June/July issue of GQ Australia. "I make my decisions about what's going to make me happy, what I think is right and what I want to do."
"Of course [the split] was hard," he said. "But at the time we were going in different directions and it's just what needed to happen. We were both super young and it was a good decision at the time -- we both needed that."
Hemsworth addressed his status with Cyrus by saying, "People will figure it out, they already have... They're not dumb." The actor had denied the engagement in an interview in April.
Cyrus last released Miley Cyrus & Her Dead Petz in August and will serve as a coach on The Voice Season 11. Hemsworth will next star in Independence Day: Resurgence with Maika Monroe.