When the Bruins and Penguins arrived at Fenway Park on Monday morning -- a crisp winter day warmer than many of Fenway Park's actual Opening Days -- they made sure to dress for the occasion. That meant the Bruins got off their bus in gorgeous throwback Red Sox uniforms:

"They're 'Field of Dreams' and a combination of '8 Men Out,'" Bruins coach Jim Montgomery joked before the game.

The team then got on the field for a group photo -- much like it was Opening Day:

Of course, what's the point of wearing all the gear unless you have a catch with it on, too?

Red Sox utility player Kiké Hernández even made it onto the field for the warm-up -- and a Tik Tok meme:

Not to be outdone, the Penguins also came out in some Bucco regalia before getting their own team photo in the visitor's clubhouse:

Goaltender Casey DeSmith -- who has his own baseball-themed mask for the contest -- donned some catcher's gear for his walk to the park:

The Penguins radio broadcaster Josh Getzoff even dressed as legendary former Pirates play-by-play announcer Bob Prince:

"Quite honestly, I'm not even sure where the idea came from," Penguins coach Mike Sullivan -- a lifelong Red Sox fan originally from Massachusetts -- said about the stunt. "Having said that, at an event like this in such an iconic stadium, I think it's appropriate because it gives us an opportunity to tip our hat to all the great players and great teams that have played in this stadium over the years."