The former Dragons, Scarlets and Gloucester centre, who won 18 caps for his country, was diagnosed with pelvic cancer in 2013.
Watkins had raised thousands of pounds fundraising in recent years for the Welsh Cancer Centre Velindre throughout his treatment. In 2018 Watkins discovered the cancer had spread to his spine and in January this year he announced it had spread to his head.
Watkins discovered the cancer after an MRI after initially believing the pain in his pack was due to the hip injury which had forced his retirement from the game in 2011.
A husband to wife Stacey and father to sons Siôr and Tal, Watkins was immensely popular.
After starting his career with Newport RFC, Watkins moved on to Llanelli where he emerged as an outstanding centre and earned himself a call-up to Wales.
Perhaps his greatest moment playing for his country came as part of the team that pulled off a historic win over Australia under Mike Ruddock.
A statement from the Welsh Rugby Union read: “We are deeply saddened by the news that former Wales international Matthew J Watkins has passed away. The squad will today wear black armbands to show their respects. All our thoughts are with MJ’s family and friends. Cysga’n dawel MJ.”
While the Scarlets paid tribute to Watkins, who featured for them more than 100 times.
“The Scarlets family are deeply saddened by the news that our former player Matthew Watkins has passed away at the age of 41,” read a statement from the Welsh club. ”‘MJ’ played 150 matches in a Scarlets jersey between 2002 and 2008, scoring 42 tries, including one against Ulster at Stradey Park that helped the Scarlets clinch the 2003-04 Celtic League title.
“He is fondly remembered as a silky-skilled, creative midfielder, who was a hugely popular figure among our supporters, the playing squad and staff at Stradey.
“The thoughts of everyone at Scarlets Rugby are with Matthew’s wife Stacey, his sons Siôr and Tal, family and friends at this sad time.”
While the Dragons also announced their sadness at Watkins’ passing.
“Everyone at Dragons Rugby is deeply saddened at the passing of our former player Matthew J Watkins at the age of 41,” read a statement.
“Matthew will be missed by so many and our sincere condolences go out to Matthew’s wife Stacey, his sons Siôr and Tal, family and friends. The thoughts of everyone at Dragons Rugby are with them all at this very sad time.”