Ulster sign Robbie Diack and Cillian Willis

Matt Williams continues his Ulster revolution with the signing of Western Province number eight Robbie Diack and Leinster scrum-half Cillian Willis.

Diack, 22, is one of the most promising back row forwards and was central to The Stormers Super-14s campaign this season.

"Robbie has made a really big impact for the Stormers and is definitely coming into the best form of his career," said Williams.

"He will add some real strength to the back row and is an explosive and smart player."

Ireland A scrum-half Willis, named in the Churchill Cup squad, brings an extra option at the base of the scrum.

"I'm really delighted to be joining Ulster, it is an exciting time for the province with a young squad and new coach and I'm looking forward to being part of it next season," the 23-year-old said.

"I've met with Matt Williams a few times recently and I'm thrilled about working under such a well respected coach. The lads that I have played alongside at Leinster all speak very highly of him."