Sean Holley will join the Scarlets coaching staff during this season's RBS 6 Nations Championship.
The former Ospreys head coach will work alongside Simon Easterby and his coaching team, the Scarlets announced.
It follows the announcement earlier this week that Scarlets attack coach Mark Jones will be part of Wales' coaching unit for the Six Nations, which starts on February 2.
Holley, 42, will work as backs and skills coach while Jones is away from Scarlets duty.
Easterby said: "To have a coach of Sean's experience, expertise and technical ability at a key time for us is vital as Mark goes away on Wales duty.
"Mark has contributed a great deal to our rugby environment and team this season and deserves his opportunity with Wales, and we are pleased to support the national set-up and his coaching development.
"Sean will be looking to continue the good work Mark has already put in place.
"We have a crucial period ahead of us while nine of our senior players are away during the Six Nations, and we need to make significant progress in the RaboDirect PRO12.
"We are fortunate, given the time-frame and being midway through the season, to have secured the services of someone of Sean's capability and background."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.