Reigning champions Connacht will launch the defence of their Guinness PRO12 title against Glasgow Warriors.
Champions Cup holders Saracens have been drawn against Toulon while Bath will meet Bristol in the Challenge Cup.
Wales international lock Lou Reed has signed a two-year contract to join Sale Sharks from Cardiff Blues.
We put the best in the Guinness PRO12 up against the best in the Aviva Premiership in our head-to-head teams of the season.
Connacht led the way at the Guinness PRO12 awards in Dublin where Bundee Aki was named Players' Player of the Year.
Watch all the highlights from a dramatic final round in the Guinness PRO12 as Leinster and Connacht booked home semi-finals.
Edinburgh were denied a place in next year's Champions Cup after Cardiff Blues came from behind to beat them in their PRO12 clash.
Leinster will take on Ulster and Connacht will host Glasgow in the Guinness PRO12 play-offs, live on Sky Sports.
All the team news ahead of the last round of regular-season fixtures in the Guinness PRO12.
Rhys Webb scored two tries at the death to hand Ospreys a 40-27 derby win over Cardiff Blues at the Principality Stadium.
Scott Williams returns from injury at Judgement Day as the Scarlets face the Dragons and Cardiff Blues tackle the Ospreys.
Catch up on all the highlights from an exciting penultimate round of Guinness PRO12 action.
Cardiff Blues kept their European hopes alive with a comfortable 28-8 Guinness PRO12 win over Dragons at the Arms Park.
Cardiff have recalled Wales international Kristian Dacey and Jarrad Hoeata for Sunday's PRO12 clash with the Dragons.
Wales wing Alex Cuthbert has signed a new contract with Cardiff Blues despite being sidelined due to injury.
Hat-trick heroes Thomas Waldrom and Ryan Crotty make our team of the week, with 12 different clubs represented.
Cardiff Blues kept their top six hopes alive with a 28-22 victory at Scarlets in the Guinness PRO12 on Saturday.
Cardiff Blues have signed Hurricanes centre Willis Halaholo on a long-term contract.
Cardiff Blues wing Alex Cuthbert has been ruled out of the rest of the season following surgery on his knee.
Cardiff Blues avenged their shock defeat in Treviso with an eight-try 56-8 thrashing of the Italians at the Arms Park.