It all began when the old friends -- who played the iconic characters Jim Halpert and Pam Beesly on the NBC comedy series -- discovered their favorite hockey teams, the Boston Bruins (Krasinski) and the St. Louis Blues (Fischer), would be competing for the Stanley Cup. Ever since both Krasinski and Fischer have been trolling one another on social media, even referencing their characters in their jabs.
However, going into Game 7 on Wednesday night, Krasinski fired the ultimate shot by bringing up some old Jim and Pam drama from "The Office" onto the ice to give Fischer the most savage diss. He invited actor David Denman, who played Roy on the long-running comedy, to the Stanley Cup finals. (For those who haven't seen the series, Roy was Pam's lackluster ex-fiancé and caused some major issues between Jim and Pam at the start of their relationship.)
While at the game, Krasinski filmed a video in his seat where he seemed to call a truce with Fischer and said he was bummed she couldn't be his plus one to the game.
"Game 7 Stanley Cup," Krasinski, who was decked out in Bruins gear, began. "Jenna Fischer, I know we've been having our ups and downs lately. I just want to say I'm really sorry you're not here. This is your seat right here."
"I was really bummed that you couldn't make it but listen, honestly, let's just have the best team win," he continued. "Both teams have been playing incredibly well and I think it's just an exciting series for hockey -- "
Krasinski's sentence was cut off when Denman appeared and handed his pal a beer. The "Jack Ryan" star thanked Denman and continued, "I just think at the end of the day it's about hockey. It's about hockey fans. Good luck."
Although Krasinski's team didn't come out on top, Fischer still had the best comeback in response to the video. "Ha. Ha. Well played," she tweeted. "Just be careful he doesn't leave you at the game."
See how the rivalry escalated in the tweets below. Michael Scott himself, Steve Carell, even picked a side!
I love you St. Louis! I love all of you who watched this game at Enterprise Center. I love all of you who watched in the pouring rain from Busch Stadium. From viewing parties and at home! We All Bleed Blue! Congratulations @StLouisBlues Stanley Cup Winners! https://t.co/sGib9JunPl