UPDATE: Muhammad Ali's respiratory condition could be more serious than any of the issues he faced during previous hospital stays, two sources told the Associated Press early Friday morning.

The AP is additionally reporting that Ali's condition is being complicated by his Parkinson's disease, which he has battled since 1984. The former three-time world heavyweight boxing champion and beloved global sports icon's condition is serious enough that daughters Laila Ali and Hana Yasmeen Ali have reportedly made the trip to the Phoenix hospital he's being treated at.

This update comes after Ali, 74, was originally listed in fair condition and only expected to stay at the hospital a short while longer.

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TMZ Sports is reporting that Muhammad Ali was hospitalized Thursday, being treated for a respiratory issue.

The former three-time world heavyweight boxing champion is currently being listed in fair condition, Ali's spokesperson told TMZ, adding that a team of doctors is by his side and that he is expected to stay at the hospital for a bit longer.

Ali, 74, attended the Celebrity Fight Night charity event, alongside other stars, just two months ago in Arizona.

This is the second such health scare that has stricken Ali within the past 18 months, as arguably the most influential athlete of all time was hospitalized twice between December 2014 and January 2015 for a recurring bout with a severe urinary tract infection.

Ali defeated that — just as he did 56 opponents over his glorious boxing career — and hopefully he'll defeat this, too.

Ali has been battling Parkinson's disease since 1984.

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