Following the spectacular inaugural event last year 'Judgement Day II' kicks-off at 2pm, when the Blues host the Scarlets in the, now, annual meeting of the four Welsh regions at the home of Welsh sport.
The Dragons face the Ospreys at 4.45pm, with an array of half-time and pre-match entertainment also on display, including former X Factor stars Rhydian Roberts, Lucie Jones and finalist and former Neath and Glamorgan Wanderers scrum-half, who recently supported Gary Barlow on tour, Tim Cronin.
At a joint event held at the Welsh capital's historic landmark Cardiff Castle on Tuesday afternoon, the four Welsh regions were united in celebrating the big regional rugby event as excitement builds for the Easter holiday clashes.
So far this season the league's Welsh derby contests have entertained more than 66,000 regional rugby supporters - with an average attendance at derby fixtures so far this season above 11,000 with more Welsh derby action yet to come.
Cardiff Blues Coach Dale McIntosh said: "The best players in Wales are under one roof and both games should be great spectacles, so let's hope the fans come in big numbers and get right behind it.
"It's all new playing at the Millennium Stadium for many of us, new for me and Johnsey (Paul John) too. The players are excited and you have got to be, because it's a great occasion.
"These games and occasions are always tight because we have a tendency to know each other as players and coaches, we work each other out so it becomes a real arm wrestle. But I am sure the youngsters are looking forward to it and we should have two great games."
Simon Easterby, Head Coach of the Scarlets said: "The Welsh derbies give a clear focus on the level of commitment, passion and endeavour that everyone involved in the regional game gives to Welsh rugby.
"The players and coaches put their all into these derbies, they mean so much and it's also reflected in our support - the crowds really have been excellent so far this season and we hope Sunday is no different.
"We approach these games differently as coaches and players - there is more at stake than just league points for all involved.
"The match-up between players in these two games will be interesting with international places up for grabs - but first and foremost we believe our players are playing for their regions and pride in the jersey."
Ospreys Captain Alun Wyn Jones said: "Regional derbies are one of the most competitive games you play at club level and as a player they're the games you'll always want to be involved in.
"This Sunday's double header will be a great occasion for our supporters and a good atmosphere is guaranteed at the Millennium Stadium, so there's plenty for our regional supporters to enjoy."
Newport Gwent Dragons international back row Andrew Coombs said: "They'll be everything you expect from big derby matches in terms of passion and physicality and these Welsh games are a big motivation for the players and coaches.
"Hopefully it will be another great advert for regional rugby and great occasion for everybody involved."