Keith Earls has signed a new deal with the IRFU which will keep him at Munster until June 2021.
The deal follows Conor Murray's contract extension earlier this month, and has also been wholly funded by the IRFU.
31-year-old Earls made his Ireland debut against Canada in 2008 and has since picked up 70 caps, scoring 27 tries in the process. His eight tries in 10 Rugby World Cup appearances across the 2011 and 2015 tournaments make him Ireland's all-time top try scorer in the competition.
He has also made 154 provincial appearances since his debut against the Ospreys in 2007 - crossing the whitewash 47 times.
Meanwhile IRFU performance director David Nucifora said: "Keith had a tough run of injuries which ruled him out of the national team successes enjoyed in 2014 and 2015 but he has demonstrated his strength of character and star quality to return and perform at such a consistently high level on the international stage.