3. Joost van der Westhuizen – 45
The former South Africa captain died aged 45 in February 2017, six years after he was diagnosed with the debilitating motor neurone disease.
Van der Westhuizen won the World Cup with the Springboks in 1995. Regarded as one of the finest scrum-halves in history, he won 89 international caps between 1993 and 2003, scoring 38 tries. He captained the Springboks for four years, including at the 1999 World Cup, before his retirement in 2003.
4. Jerry Collins, aged 34
The former New Zealand flanker and his wife Alana Madill have died in a car crash in France at the age of 34, in June 2015.
Collins won 48 caps for the All Blacks having made his debut in 2001, scoring five tries during a career that saw him become one of the most feared back-row players on the pitch due to his sheer strength and physicality.
He also featured in the New Zealand side that thrashed the British and Irish Lions in 2005, and was the cousin of former All Blacks captain Tana Umaga.