Says TMZ:

Before Bryce Harper sent a baseball to another planet in walk-off fashion Thursday night … he told a heckler to “shut the f**k up”!

The Phillies superstar has heard constant chirping from fans this year after signing a 13-year, $330 MILLION contract this offseason … ’cause he hasn’t quite performed up to expectations.

So, after he was 0-for-3 to start the Phillies’ game against the Cubs … a fan let him have it on his way back to the dugout.

“$330 million, 0-for-3,” the fan said …

“Shut the f**k up, stupid!” Harper clapped back.

Of course, there’s no doubt the fan did exactly that just an inning later … ’cause in the bottom of the 9th with the bases loaded — Harper sent a baseball 413 feet to give the Phils a series sweep over the visiting Cubs!!!