They shared three premierships with Canberra and some memorable Test victories but, when it comes to State of Origin, Mal Meninga and Ricky Stuart are bitter enemies.
Their relationship soured so much last year that former Raiders' teammate Laurie Daley felt the need to broker peace talks between the feuding pair.
"A football game will never get in the way of any friendships I've made in rugby league," declared Stuart at the time.
Their intense rivalry personifies Origin's "mate against mate" mantra on which the concept was born in 1980.
In many ways, their passion for their state and for their players above all else is why Origin is riding a massive high and is the envy of most other sports in Australia.
Their friendship faces another test on Wednesday night when Queensland and NSW fight out Origin's 16th series decider.
It might surprise some to know Stuart holds a 10-8 head-to-head advantage over Meninga in their 18 Origin clashes as rival players and coaches.
Stuart won eight of their 13 meetings on the field between 1990-94 but trails Meninga 3-2 after taking over from Craig Bellamy as NSW coach in 2011.
Stuart has had a good run in Brisbane deciders.
He was halfback in the NSW side that denied Meninga a winning Origin send off at Suncorp Stadium in 1994 and then enjoyed victory as coach in 2005, the last time the Blues won a decider at Suncorp Stadium.
He also produced a man-of-the-match performance to deny Meninga a series win in Sydney when the Queenslander was Maroons captain in 1992.
Meninga was at his jovial best on Origin eve, jousting with journalists about some of the stories they "make up".
"There's got to be some sort of story. You blokes make things up these days - no, seriously," grinned Meninga.
"Some of the things that come out of your minds or your mouths, fair dinkum, leaves a lot to be desired.
"Apparently, Dane Nielsen's no good at the moment and I'm under pressure (to keep my job).
"Fair dinkum, what's going on with you blokes?"
On a more serious note, Meninga said it was extremely satisfying that Origin was now watched by an audience of four million and was a world-wide product.
"That's good and we're happy we can provide that sort of entertainment," he said.
"I enjoy being involved - I love rugby league. It can't get any better than this, to be honest," he said.
Stuart played down any animosity with Meninga but did admit he was a little jealous of his Origin rival.
"Mal and I will probably sit back and watch two teams that are well prepared and have a brilliant game of football," he said.
"I want what Mal's got at the moment and that is what the rivalry is.
"I want something he's got and he doesn't want to give it to me.
"It's been a very healthy, competitive series and let's hope tomorrow night is the same thing."