A minute’s silence will be held before Rhinos’ derby against Wakefield Trinity Wildcats, the beginning and end of which will be marked by the sounding of the hooter, rather than the traditional referee’s whistle.
The 92-year-old, who had been ill for some time, died in hospital on Saturday, just five months after retiring from his various roles with the club.
Though he never played for Leeds, Watts was associated with the club for more than 40 years and was timekeeper from 1975, when the role was introduced, until the RFL took it in-house in recent seasons.
Speaking to the Yorkshire Post in 2004, Watts - whose wife Audrey died last year - recalled watching his first Leeds game as a 12-year-old at Christmas, 1938.
“The rugby pitch was frozen and they had to play on the cricket field which was protected by its longer grass,” he said.
“The crowd was about 12,500 and we beat Salford 5-0. It was the start of a love affair.”
Watts - who served in the Royal Navy during the second world war - was a scrum-half with East Leeds in his younger years and his work with the club ranged from fundraising to helping out on the training ground, where he turned up for work every day at 7am to greet the players and help out.
When Leeds won the Super League title in 2004 he was chosen by the Rhinos players as one of only three people outside of the playing squad to receive a Grand Final winner’s ring.
Then-coach Tony Smith said at the time: “Billy is always there for the players and coaches, come rain or shine and whenever you walk into work he is there with a smile on his face, win, lose or draw. That is important in a club environment and Billy thoroughly deserves this.”
Watts was clubman of the year in 1999 and in 2003 was presented with an outstanding service award by the Leeds ex-players association.
Rhinos coach Brian McDermott led tributes.
“Billy has been an important and very popular part of the football staff for nearly 30 years,” he said.
“Having served his country in the Royal Navy during in World War II Billy had a great work ethic and a great sense of humour.
“He had an outstanding ability to keep smiling during tough times. He was certainly ‘one of us’ and we will miss him at our training base.”
McDermott added: “I’ll personally miss his hand shakes and chats after a win or a loss. He always knew what to say and was able to give his perspective on any given situation having seen Leeds teams play for over 70 years. He will be sadly missed by everyone who knew him.”
Rhinos chief executive Gary Hetherington added: “Billy is unique, having achieved legendary status with Leeds Rhinos without having played for the club.
“When I played in the late 1970s he travelled with the team as time keeper and he was in and around the team all the time, helping the players.
“He had a variety of roles and he really came into his own after a bad loss. At 7am the following day he would be the first in at training, with his smiling face, reminding everyone it was a new day.
“He was inspirational in that regard. He has been at the heart of the club for so long and a key member or our back room staff.
“His enthusiasm, good nature and dedication has been inspirational and he will be sadly missed.”
Past and present Leeds players, staff and fans took to Twitter to voice their memories.
Danny Ward, a member of the 2004 title-winning team, summed up their sentiments by Tweeting: “Heartbreaking to hear the sad news on @leedsrhinos #Legend Billy Watts. Absolute diamond who’ll be greatly missed.”