Scarlets will take on Ospreys in the EPCR Challenge Cup Round of 16 at the Swansea.com stadium on Sunday, April 6 with a 5.30pm kick-off.
Tournament organisers have confirmed fixtures for both the Champions and Challenge Cup knockout stages, with the West Wales derby one of the final games of a bumper weekend of action.
The match will be televised live by S4C.
Full ticketing details will be announced shortly.