Munster's progress to the European Cup semi-finals has meant their Celtic League game against Ulster - postponed on January 4 due to adverse weather conditions - has been re-arranged for April 29 at Ravenhill, kick-off 7pm.
The Munstermen beat Gloucester 16-3 at Kingsholm on Saturday to set up clash with Saracens at the Ricoh Arena in Coventry on April 27.
It means a congested end to the season for Ulster, who have five league matches remaining, but represents an opportunity to claim some vital points with every game now crucial for Matt Williams' side in their bid to gain European Cup qualification.
The rearranged date means that Ulster will play two home games within the space of four days.
Ulster captain Rory Best said: "The mood in the camp remains upbeat and the players are pleased to have the fixture confirmed so they can get the training mix right.
"Our games against Munster are always massive and we are pleased now that we have the date confirmed so we can get on with preparation.
"We have four home games left and each one is vital for this season and seasons ahead.
"We know that Tuesday evening isn't a traditional Ravenhill night but we hope that our supporters will come along and recreate the infamous Ravenhill roar," he added.
With Munster playing their semi-final against Saracens just two days before the game, Ulster will be hoping to score a much-needed win over the men in red, who have been in serious form of late.
Ulster Rugby chief executive Michael Reid said: "There were over 12,000 tickets sold initially for the game on January 4 and hopefully when supporters take into account the fact that we are playing our interprovincial rivals and with so much at stake for Ulster in terms of our position in the Magners League table, it won't matter that the game is going to be played on a Tuesday.
"It's a perfect opportunity to claim a scalp from one of the sides in contention for Heineken Cup success this season and boost our league points as well."
England flanker James Haskell insists he will be pushing as hard as possible to be back from a toe injury in time to make his case for a spot in Eddie Jones' side looking to defend their RBS 6 Nations title next year.