More specifically, both benefited from Hamilton Southeastern High School in Fishers, Ind..
Now, the shooting guards will meet for the first time in a live game Saturday in East Lansing in a rivalry game between two teams undefeated in the Big Ten.
"It has been a long time," Irvin said. "I don't think I've ever actually played against him in a real game before. This I going to be the first time against each other."
With the potential of matching up with his former teammate, Harris said it should bring plenty of fun to the meeting.
"Even in practice we pretty much played on the same team the whole time, so it's definitely going to be fun," Harris said.
The pair both said they have been keeping up throughout the season to varying degrees.
"We check up on each other every now and then," Harris said. "Not like every day or anything but we check up on each other."
Irvin said that contact hasn't been a part of the past week leading up to the clash at Breslin Center.
"With us playing them this Saturday, there will be not be any talks between me and him," he said.
Irvin went as far as to say the contact they had a week ago might be it for a while, but that could depend on the outcome of their first college clash.
And if Harris leaves for the NBA at the end of the season as many expect, it could be one of only two chances to get a let up on the other.
Bragging rights are on the line.