The Welsh Rugby Union has announced former Wales captain Sam Warburton is joining the coaching team as a technical advisor.
Warburton was capped 74 times for Wales and 175 times for Cardiff Blues.
The defensive duo join Stephen Jones, Jonathan Humphreys and Neil Jenkins in the coaching team with all five of Pivac’s assistants former Wales internationals, three of whom are former Wales captains.
Hayward returns to the WRU where he had a successful stint as Wales U20 head coach and National Academy skills coach before joining the Scarlets as defence coach in 2014.
Whilst in Llanelli Hayward helped the region to their first Guinness Pro12 title in 2017 and to reach the Pro14 final and the Champions Cup semi-final a year later.
Warburton, who led his country more times than any other Welshman and led the British & Irish Lions on two successful tours, returns to the international game in a new capacity.
Former Head Coach Gatland has returned to New Zealand to take up the role of head coach at Super Rugby outfit Chiefs before also leading the British and Irish Lions to South Africa in 2021.
Former attack coach Rob Howley is currently under investigation for an alleged breach of World Rugby betting rules. He had previously been linked with the Italy head coach role.
Robin McBryde has joined Leinster as forwards coach, while place-kicking expert Neil Jenkins is remaining within the Wales set up under new Wales coach Wayne Pivac.
Wales finished in 4th place at the World Cup after losing to New Zealand in the Bronze match.