Interim Wales head coach Rob Howley was delighted to confirm the appointment.
"Mark is an important addition to the coaching team," said Howley. "He has played the game at the highest level and developed his coaching skills during his time with the Scarlets.
"He is a 'hands on coach' and understand how our environment works which is important leading into the tournament.
"I'd like to thank Simon Easterby and the Scarlets for allowing Mark to join us and to start work immediately.
"We have always been an integrated coaching team and Mark will be a great addition alongside Robin, Shaun and Neil."
Mark Jones said: "It is a huge honour for me to be called upon by Wales for the forthcoming Six Nations and I am looking forward to this exciting opportunity for me to develop further as a coach.
"It will help me to explore new ideas and gain wider experience that I hope will in turn benefit my full-time role with the Scarlets region.
"I am very grateful to the Scarlets for agreeing to support me in my progression as a coach and backing me to take this opportunity at international level. It will be a privilege to work with the Welsh team and a group of talented international players and coaches."
Mark Davies, Chief Executive of the Scarlets said: "As a region, our belief is to develop and support the talent we have invested in at the Scarlets and to see people reach their full potential. That philosophy applies as much to our coaching set-up as it does to our players.
"This will be an important landmark and a valuable experience for Mark as he progresses as a top-class coach. I am sure he will give all he has to Wales in the forthcoming campaign with his trademark energy and determination. We all wish him well and he has our full support in this exciting opportunity."