On Saturday 26 July the BT Sport Cardiff Arms Park will host the first leg of this year's tournament - now in its fifth year - with two of the Regions qualifying for the Series Final at the Twickenham Stoop on Friday 8 August.
"The bond between the Premiership Rugby clubs and our friends in the Welsh Regions gets stronger every year," said Premiership Rugby Chief Executive Mark McCafferty.
"I am delighted therefore to confirm that they will take part in the Premiership Rugby 7s. The tournament has grown each year and the participation of the Welsh Regions will take it to a new level."
Premiership Rugby can also confirm that all four group stages of the Premiership Rugby 7s and the Series Final will be covered live on BT Sport. The 2014 Premiership Rugby 7s Series Champion will go on to play in the World Club 7s on 16 and 17 August at Twickenham.
Mark Davies, Acting Chief Executive of Regional Rugby Wales which represents the four Welsh Regions said: "The Regions have never played each other in a 7s tournament before so there is a lot of pride at stake as well a the opportunity of a place in the Series Final and the chance to be part of what will be a very big family occasion up at the World Club 7s at Twickenham in August.
"We will create a festival of rugby on 26 July here in Cardiff showcasing not only the professional game in Wales but also the investment and progress being made in age-grade rugby and the women's game.
"Having announced our exciting three-year sponsorship agreement with BT Sport this week as well, it shows we have a positive partnership that will go forward between BT Sport and our four Welsh Regions.
"We know for sure that Anglo Welsh rugby contests ignite plenty of excitement and passion amongst our supporters and we hope our involvement will add a real edge to the event."
The 2014 Premiership Rugby 7s Series is split into four qualifying group stages, and a Series Final, contested by all 12 Aviva Premiership Rugby clubs and the four Welsh Regions. The only 7s event where you can watch the Aviva Premiership Rugby sides battle against one another.
Group A sees the four Welsh Regions kick off the tournament at BT Sport Cardiff Arms Park contested by Cardiff Blues, Newport Gwent Dragons, Ospreys, and Scarlets.
Thursday 31 July sees Gloucester Rugby host Bath Rugby, Exeter Chiefs, and London Irish in Group B.
Twenty four hours later Group C features Northampton Saints, Harlequins, London Wasps and Saracens at Franklin's Gardens.
Completing the group stages on Saturday 2 August at Kingston Park, Newcastle are Leicester Tigers, Sale Sharks and Worcester Warriors who will take on the hosts Newcastle Falcons for a place in the Series Final in Group D.
· For tickets and more information visit: www.premiershiprugby.com/7s or follow @premrugby_7s
Saturday 26 July
BT Sport Cardiff Arms Park
Teams: Cardiff Blues, Newport Gwent Dragons, Ospreys, Scarlets
Thursday 31 July
Kingsholm Stadium, Gloucester
Teams: Bath Rugby, Exeter Chiefs, Gloucester Rugby, London Irish
Friday 1 August
Franklin's Gardens, Northampton
Teams: Harlequins, London Wasps, Northampton Saints and Saracens
Saturday 2 August
Kingston Park, Newcastle
Teams: Leicester Tigers, Newcastle Falcons, Sale Sharks and Worcester Warriors
Friday 8 August
Two qualifiers from each Group
The Twickenham Stoop