Michael Owen has been appointed Wales captain for the RBS 6 Nations clash against Scotland at Murrayfield on March 13.
The Newport Gwent Dragons number eight will take over from full-back Gareth Thomas, who broke his thumb during last Saturday's stunning victory over France in Paris.
Wales need to beat Scotland, and then topple Ireland in Cardiff six days later, to achieve their first Grand Slam since 1978.
Owen's promotion was widely touted following the French game, and he now steps up for one of the biggest games in Welsh rugby history.
''We are in a position of strength in making the appointment, as Michael was one of the primary candidates who undertook the interview process which eventually appointed Gareth,'' said Wales coach Mike Ruddock.
''We know he has the right credentials for the job, and he is a player I have worked with before at both regional and international level for some time.
''The current crop of players in the Welsh team is full of young leaders, but we are hoping the role will bring out the best in Michael, as it did during the second-half against France.
''He proved himself in that game when the chips were down, and we have always known he was a Wales captain of the future.''
Thomas will also miss the Ireland finale, clearing the way for Owen, who becomes the 122nd Welsh captain, to mastermind Wales' RBS 6 Nations title push.
''Obviously, to be asked to captain your country is a fantastic honour, but it is taking a while to sink in with me at the moment,'' Owen said.
''It will be a pretty surreal experience to be honest, to lead the team out in such a massive game, and I can't really imagine what I will be feeling at this stage.
''Alfie (Gareth Thomas) is a unique character, and so there is no way I can recreate his style of captaincy, but the key thing I have learnt from him is that you need to be yourself to get it right.
''There are plenty of leaders in this side who will all make the job easy, and it could really have been any one of a number of players who could have got the nod.
''It is a great time to be the Wales captain, but we all know we only got to the stage where we have started to win a few games through a lot of hard work and determination over a number of years, and we must continue in the same way going forward.''
Wales have won just once at Murrayfield in 20 years, although current RBS 6 Nations form means that they will travel to Edinburgh as overwhelming favourites.
Peter O'Mahony was named man of the match against England last month
21 April 2017, 7:22pm
Peter O'Mahony's performance in the RBS 6 Nations finale for Ireland against England was crucial to his selection for the British & Irish Lions on Wednesday, Ireland and Lions defence coach Andy Farrell has revealed.