At every Australian Open tennis great Ken Rosewall writes a heartfelt letter and leaves it for Roger Federer in the players' locker room.
It's just a short note on a single slip of paper in neat hand-writing, which Rosewall gives to the doorman.
"I just write a simple half-page," Rosewall told The Australian newspaper on Monday. "Good luck. Hope the family's well. That's the extent of it.
"My accreditation pass doesn't allow me to get into the dressing room. I don't want to invade his privacy or bother him at all, so I just figure I'll write him a note."
He said he had met Federer several times and would like to see more of him, "but obviously his time is pretty well taken care of".
"He's admired by millions of people, including me. He's been winning major championships for a long time," added 83-year-old Rosewall, who won eight Grand Slams.
"Now he's 36 and still doing it. Now he's still carrying himself the way he does. He's done an amazing thing for tennis."
Federer cherishes the Australian great's letters and has spoken often about his affection for the game's enduring legends.
"I think he's a wonderful man. We don't speak about him enough," Federer told the newspaper.
"I love that generation of players with Tony Roche, Rod Laver, Ken Rosewall, Roy Emerson ... I know Ken's a few years older, but I know he had a tremendous career.
"So to be in the same break as these guys, it's a great feeling. I love these guys."
Rosewall won the 1972 Australian Open as a 37-year-old. Federer is defending the title as a 36-year-old.