For a long time in his Super Rugby career, the only second row partnership Rob Simmons knew was one with James Horwill.
Simmons and Horwill shared the field for almost a decade with the Reds, winning the 2011 championship together, and they took their partnership to the Test arena as well.
Horwill announced his retirement from rugby on Monday night and though it's been four years since the pair have played together, Simmons still rates their duo as one of his most significant.
"It's a pretty special one," he said.
"He's a close friend of mine and that was built through our relationship on the field. We played, I played most of my rugby with him so it's hard to compare to any other relationship really.
"It was the longest (relationship) - that's in rugby.
"It was awesome to play with him, I love playing with him and we've got a special bond on and off the field."
Simmons said the duo complemented each other in their style, with their pairing flourishing under Ewen McKenzie at the Reds.
Simmons admitted he was surprised by the announcement, which came on Monday night but doesn't expect his friend to be lost to rugby.
"Typical Kevvy, just dropping it on everyone and not wanting much of a fuss," he said.
Congratulations on a fantastic career @JHorwill Always loyal, commited and above all excited to play for his respective teams. Well done mate and look forward to waking up without a sore back most days!!— Dean Mumm (@DeanMumm) April 15, 2019
A new beginning Big Kev - loved the intensity, passion and team ethos you represented. A great player, a ripper bloke. Well done!— Brendan Cannon (@canno02) April 15, 2019
Horwill started his Super Rugby career with the Queensland Reds, playing 116 matches and captaining the side to the 2011 Super Rugby championship.
The lock, nicknamed Kev, made his Wallabies debut in 2007 and narrowly missed out on that year's World Cup squa.d
His time would come four years, captaining the Wallabies in the 2011 Rugby World Cup, capping off a dream 2011 season.
Horwill was a surprise omission from the 2015 Rugby World Cup squad and the Queensland veteran made the move to English club Harlequins at the end of that season.
He returned to Australia under the Giteau Law in the 2016 England series and played the last of his 62 Tests at Suncorp Stadium in the first game of that series.
The 33-year-old played four seasons at Harlequins, captaining the side in recent seasons.
Horwill announced his retirement on Monday night, thanking fans, teammates, coaches and his family for their support.
"The time has come for me to retire from professional rugby. I have given this great game everything I have & I feel I can no longer give what is needed to play at this elite level," he wrote.
"Rugby has been a big part of my life for many years, never in my wildest dreams would I have envisaged the incredible journey it has taken me on.
I’ve had the privilege and honour to not only play, but captain my state, country and club on a number of occasions over my 14-year career."
Horwill listed that 2011 championship and leading the Wallabies as among his career highlights.
"Winning the Super Rugby title and being asked to captain my country are some of the moments I’ll cherish for a lifetime," he wrote.
"I want to thank all the coaches and staff I’ve worked with over my career, you have all made an impact and shaped me into the player I am today."
The Brisbane-born and bred Horwill had his fair share of injury setbacks, including a gruesome hamstring injury that cost him a season in 2012 and he was quick to thank medical staff for the role they played.
"Special thanks must go to the physios and doctors, who have put me back together. We spent more time together than I would have liked, but without your care, I wouldn’t have played as long," he wrote.
"To all the players I have had the pleasure to play with (and against), you are why I have loved my career so much. We have made some unforgettable memories and I know I have friends for life.
"To the fans all over the world,who have supported me throughout my career, thank you .
"My job would not have existed without you; you are what makes this game so special."
Horwill will play on with Harlequins for the rest of the English season.