12:00 PM PT -- Tony is providing some more information on his health scare ... saying he suffered a heart attack.

McGregor added he had a stent put in this afternoon ... and is already back to feeling well enough to enjoy some sweet and sour chicken.

"See ya later suckers," Tony said on Instagram.

Conor McGregor's father, Tony, was taken to the hospital after experiencing chest pain on Thursday ... but fortunately, it sounds like everything's going to be just fine, TMZ Sports has learned.

We're told Tony is currently at a top-notch medical facility near his home in Ireland ... with several family members, including Conor, present for support.

Our sources tell us Tony arrived at the hospital sometime this morning ... and after undergoing some tests, is expected to be released.

Tony -- originally from Liverpool -- was responsible for getting Conor into sports at a young age ... and introduced him to kickboxing.

He worked numerous jobs to provide for the McGregor family ... and it appears he now spends his time fulfilling his duties as owner and captain of the "188" private yacht.

Tony most recently showed support for Conor at his "Road House" premiere back in March ... posing with the entire McGregor clan at the event supporting the movie.

We've reached out to Conor's team for more information ... so far, no word back just yet.