Gloucester lock Ed Slater has been diagnosed with Motor Neurone Disease and retired from rugby with immediate effect.
The 33-year-old, who joined Gloucester from Leicester in 2017, represented England Saxons four times during his career.
MND is a degenerative condition that affects the brain and nerves.
Gloucester revealed in a statement that Slater has been undergoing tests for six months and that they have now opened a JustGiving page.
The statement read: "Gloucester Rugby is deeply pained to announce that Ed Slater has been diagnosed with Motor Neurone Disease (MND).
"Following six months of testing, Ed's diagnosis was confirmed last week and as a result, with the support of his family, friends and Gloucester Rugby, he has made the difficult decision to retire from professional rugby with immediate effect.
"Everyone at Gloucester Rugby - players, management and staff - are entirely committed to supporting Ed, his wife Jo and his three children in whatever way required. We know the same will be true of Gloucester and Leicester fans, and the wider rugby community.
"While Ed, his family and the Club take time to determine next steps, Gloucester Rugby have opened a JustGiving page.
"The direction of these funds will be determined in due course, whether it be supporting Ed and his family directly and/or a selected MND charity.
"Neither the club nor the Slater family will be making any further comment at this time and kindly request that those wishes be respected."
Slater made three appearances for Gloucester in the Premiership last term, most recently in January, and played 78 top-flight games in total for the Cherry and Whites.
During his seven-year spell at Leicester, he won the Premiership title once, in the 2012/13 campaign, and captained the Tigers for two seasons.
Slater began his career with Australian side Eastern Suburbs and enjoyed a stint with Nottingham in the Championship before joining Leicester in 2010.
Gloucester said they were grateful for support already received by the My Name'5 Doddie Foundation.
The Foundation was set up by former Scotland and British and Irish Lions lock Doddie Weir, who revealed in June 2017 that he was suffering from MND.
Weir has been driven to help fellow sufferers and seek ways to further research into an, as yet, incurable disease.
Former rugby league player Rob Burrow was diagnosed with MND in 2019, with the ex-Leeds Rhinos star awarded an MBE in April for his services to his sport and the MND community.