Paul Pierce Begins 8-Hour Walk To Work After Celtics Lose To Knicks

Paul Pierce really IS the "Truth" -- 'cause the Celtics legend kept his word and started an eight-hour trek to the Fox lot after guaranteeing his old team would beat the Knicks on Wednesday ... and he's documenting the whole journey.

Pierce talked a big game prior to Game 2 of the Eastern Conference semifinals ... saying if the Cs didn't even things up at 1-1, he'd use his legs as transportation to get to work the next day.

"If the Celtics lose Game two at home, I'm walking here tomorrow," Pierce said on "Speak."

"Fifteen miles! I'm walking here! In my robe, no shoes on, barefoot, if the Celtics lose tonight."

He took it even further ... saying he would put his house on the game -- 'cause he thought there was a better chance seeing a dinosaur outside the studio than New York taking home the win.

Welp, the Celtics did not win ... as Knicks forward Mikal Bridges blocked Jayson Tatum's game-winning shot attempt, leaving Beantown stunned.

Shortly after the game went final ... the 47-year-old took to X to show off what his walk will look like -- and his phone stated it would take eight hours to do 20 miles.

The rough stats didn't deter Pierce, though ... as he posted himself beginning the long walk down to the FOX Lot in his robe. It's unclear how far into the journey he is, or if he is actually barefoot, but he has seven hours until his show goes live.