British and Irish Lions captain Sam Warburton will miss the Six Nations after the Welsh Rugby Union announced on Friday he had undergone knee surgery.
The 29-year-old backrow forward -- who captained the Lions to the thrilling1-1 Test series draw with world champions New Zealand earlier this year -- took the decision to have the operation after consulting with the WRU.
"With Warburton currently sidelined with a neck injury, the proactive approach was taken with a view of ensuring he returns to action fully fit. The recovery is anticipated between 4-6 months," read the WRU statement.
INJURY UPDATE: @samwarburton_ has undergone surgery to resolve a knee injury. Currently sidelined with a neck injury the proactive approach taken to ensure he returns fully fit. Timeframe 4-6months.— Welsh Rugby Union 🏉 (@WelshRugbyUnion) December 8, 2017
Warburton, who also led the Lions to a Test series win over Australia in 2013, said he was looking forward to returning to the fray.
"In close consultation with the WRU and Cardiff Blues (his club) we decided it would be proactive to have surgery now on a knee injury and I'm looking forward to returning to action fully fit," he added.
The Six Nations runs from February 3 to March 17 with the Welsh getting their campaign underway at home to Scotland.
Wales kicks off its Six Nations campaign on Saturday February 3, hosting Scotland, kicking off at 2:15pm local, Sunday 1:15am AEDT.
Six Nations 2018
Saturday February 3
Wales vs Scotland, Millennium Stadium, 2:15pm local, Sunday 1:15am AEDT
France vs Ireland, Stade de France, 4:45pm local, Sunday 2:45am AEDT
Sunday February 4
Italy vs England, Stadio Olimpico, 3pm local, Monday 1am AEDT
Saturday February 10
Ireland vs Italy, Aviva Stadium, 2:15om local, Sunday 1:15am AEDT
England vs Wales, Twickenham, 4:45pm local, Sunday 3:45am AEDT
Sunday February 11
Scotland vs France, Murrayfield Stadium, 3pm local, Monday 2am AEDT
Friday February 23
France vs Italy, Stade de France, 8pm local, Saturday 6am AEDT
Saturday February 24
Ireland vs Wales, Aviva Stadium, 2:15pm local, Sunday 1:15am AEDT
Scotland vs England, Murrayfield Stadium, 4:45pm local, Sunday 3:45am AEDT
Saturday March 10
Ireland vs Scotland, Aviva Stadium, 2:15pm local, Sunday 1:15am AEDT
France vs England, Stade de France, 4:45pm local, Sunday 3:45am AEDT
Sunday March 11
Wales vs Italy, Millennium Stadium, 3pm local, Monday 2am AEDT
Saturday March 17
Italy vs Scotland, Stadio Olimpico, 12:30pm local, 10:30pm AEDT
England vs Ireland, Twickenham, 2:45pm local, Sunday 1:45am AEDT
Wales vs France, Millennium Stadium, 5pm local, Sunday 4am AEDT