Last season's Judgement Day event saw a then record 52,762 pass through the turnstiles, with around 5,000 supporters significantly boosting expected attendance figures by turning up on the day to get their tickets.
"We will have the capacity to process a large amount of tickets on match-day again this year, but we also have our print at home service available and would encourage any supporters planning on making the trip to the capital at the weekend to book their tickets in advance," said a WRU ticket office spokesperson.
"With over 60,000 fans already booked in the atmosphere at Principality Stadium promises to be electric once again this year and we are very much looking forward to setting a new Guinness PRO12 record on Saturday."
The previous Guinness PRO12 record prior to JDIII, 51,700, was held by an Irish derby clash at the Aviva Stadium, between Leinster and Munster, in 2014.
The annual Judgement Day event, now in its fourth incarnation, more than doubles nearly every other attendance figure in Guinness Pro12 fixture list so far this season and has been tipped to become a guaranteed capacity occasion in the Cardiff capital by Welsh Rugby Union chairman Gareth Davies.
The only comparable fixture to Judgement Day this year to date, is again the Munster versus Leinster derby which attracted 43,108 to the Aviva Stadium last month.
Tickets for Judgement Day IV have been frozen at 2015 prices and can be purchased now at £10 per person (booking fees apply) from www.wru.wales/tickets - where print-at-home is available - by calling 0844 847 1881 or in person from the WRU Ticket Office on Westgate Street.
Season tickets purchased from either of the home teams - Blues and Dragons - include access to Judgement Day IV, with fans asked to liaise with the respective box offices.
Both matches will be shown live on television with BBC Wales showing the first match and S4C.
JUDGEMENT DAY IV
Saturday 30th April 2016
Match 1: Cardiff Blues v Ospreys (BBC Wales) - kick off 2.30pm
Match 2: Newport Gwent Dragons v Scarlets (S4c) - kick off 5pm
52,762 25/04/2015 Millennium Stadium Blues v Ospreys; Dragons v Scarlets
PREVIOUS TOP FIVE ATTENDANCE FIGURES IN THE GUINNESS PRO12 BEFORE JUDGEMENT DAY III:
51,700
29/03/2014
Aviva Stadium
Leinster v Munster
50,645
02/10/2010
Aviva Stadium
Leinster v Munster
48,365
04/11/2011
Aviva Stadium
Leinster v Munster
48,000
31/12/2006
Lansdowne Road
Leinster v Ulster
46,280
06/10/2012
Aviva Stadium
Leinster v Munster
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