AshtonKutcher911Tweet.jpgAshton Kutcher is the king of Twitter ... but even kings make bad calls.

Kutcher got very enthusiastic on Sunday (the 10th anniversary of the Sept. 11 attacks), Tweeting, "This [is] without a doubt the greatest day of the year!"

Of course, what Kutcher was actually referring to was the start of football. The Tweet continued, " ... Hello football my old friend. Let's us mingle for the next 5 months."

But after getting backlash from followers, the actor backtracked, saying:

    "I got mad respect for the people that suffered in 9/11. Pls don't twist my enthusiasm. ... Hindsight...Yeah, that was probably a poorly worded tweet."