Munster head coach Anthony Foley has died suddenly at their team hotel in Paris.
Foley, 42, died overnight at the hotel, where the team were staying prior to Sunday's game against Racing 92.
The European Champions Cup game was postponed following the former Ireland international's death.
A statement by the Irish Rugby Football Union said: "The IRFU and Munster Rugby pass on our deepest sympathy to all of Anthony's family and friends."
It added: "We ask for privacy for the family at this sad time."
Foley is survived by his wife Olive and two children.
A decorated playing career
Foley, whose father Brendan also played for Ireland, made 201 appearances in the back row for Munster in a playing career that spanned 13 years.
He made his debut in 1995 against Swansea in the province's first match in the Heineken Cup - a competition in which he would later captain his side to victory in 2006, having twice finished as a runner-up (in 2000 and 2002).
He would also captain Ireland three times in winning 62 caps, having made a try-scoring debut in the Five Nations defeat by England in January 1995.
He was replaced as Munster captain by Paul O'Connell for the 2007-08 season, at the end of which he announced his retirement and joined their coaching staff.
Foley initially took over as Munster forwards coach in 2011 - a role he briefly undertook with Ireland during the 2012 Six Nations - before graduating to head coach in 2014 after the departure of Rob Penney.
Munster appointed South African Rassie Erasmus as the club's director of rugby in July but Foley's job title remained head coach.
'One of our game's truly great guys'
BBC Sport's Tom English: This is hard to comprehend. Incredibly sad. One of Munster's all-time greats.
Glasgow Warriors coach and former Scotland international Gregor Townsend: A sad day for rugby. Hugely influential figure in the game. A good man gone too soon. RIP Axel.
Welsh Rugby Union: Unbelievably sad news. Thoughts and prayers with all Anthony's family, friends and colleagues. RIP
Former Ireland coach Eddie O'Sullivan: It is hard to get your head around what has happened, a young man in the prime of his life taken away so suddenly.
Former Scotland international Craig Chalmers: Can't believe the shocking news about Anthony Foley. One of our games truly great guys and always a Munster and Irish rugby legend.
Former England international Brian Moore: Just heard the terrible news of the death of Munster's Anthony Foley - thoughts with his family - very sad indeed.
England international Mike Brown: Absolutely terrible and sad news. Thoughts are with all his family, friends and everyone at Munster.
World Rugby chief executive Brett Gosper: Shocked by the tragic news of Anthony Foley. All at World Rugby send our heart-felt condolences and thoughts to family, friends and Munster.