Ospreys take on Toulouse, while Scarlets are at home to Exeter.
KO for both games is at 13:35
More top news
A generally dry and mild night with showers confined to inland areas. A few mist patches are likely by the early hours!
After weeks of doubt, Joe Ledley has been included in Wales' twenty-three-man squad for next month's Euro 2016 finals.
Hundreds of fans have signed a petition calling for football fanzones in Wales so supporters at home can share in the atmosphere.