Following the grand final, the Panthers' centre will be heading to the Bulldogs on a four-year deal worth $3.3 million.
The duo have played alongside each other at school, club, state and international levels, labelling themselves as “brothers” off the field.
It's fair to say this Sunday's fixture will have some extra feeling in it for both Crichton and To'o.
"I grew up with him and he's been my best mate ever since footy started so it will be emotional and I think it will hit me at the end of the game,” Crichton told NRL.com.
“I'm pretty excited to end the season on a high and finish the way we want to.
“At the start of the year I did picture this week and just hoping that we would get here.
“Each week with the boys was just about focusing on what we needed to do to get better and be better as a team to get here.”
While Crichton has mixed emotions about what's to come, the extent of the situation is only starting to sink in for To'o.
“It's pretty sad but I've just been soaking up the days this week and making the most of it,” To'o said.
“Coming through the system together, he's pretty much a brother too, and knowing we've been there from the start together and grown together, it does make me a bit emotional.
“We've been through a lot together.
“Even though he's always been bigger and taller than me, I'm older so I did take him under my wing a bit when we were younger.
“He's obviously still going to be there throughout the rest of my life and although it's going to be devastating, I can't wait to see what the future holds for him.
“I just want to put the work in this week and make sure we get the job done for each other.”