Back in February, rumors started going around that MILEY CYRUS' mom Tish had an affair with BRET MICHAELS.

--Supposedly it started last December, when Miley and Bret were recording some music together, including that new version of "Every Rose Has Its Thorn".

--Well, now that Tish and BILLY RAY CYRUS are officially getting divorced, there's a lot of speculation that Bret was the reason.

--"Us Weekly" is leading the charge, although they seem to be a little behind on the facts. They say, quote, "When Billy Ray learned of it . . . as well as at least one other fling . . . he filed for divorce October 27th."

--So they're insinuating that Billy Ray JUST learned about the affair . . . when the allegations have been floating around for almost NINE MONTHS.

--A so-called "source" tells the "Star" tabloid, quote, "Billy Ray suspects there's been something going on between his wife and Bret for a long time. She fits the profile of women Bret usually goes for: skinny, big boobs and blonde hair."

--Reps for both Tish and Bret are denying the affair. (--There's no word who that OTHER guy "Us Weekly" mentioned might be.)

Photos of the Cyrus Family

via Showbiz » The Complete Sheet » Wise Brother Media.