The Welsh side will be looking to grab a victory at Parc Y Scarlets and leapfrog their opposition in the standings.
The reverse fixture was held on the opening weekend of the competition, with Ulster sneaking a 15-13 victory at the Kingspan Stadium.
Historically, the Ulstermen have had the better of the fixture, winning 17 of their 32 fixtures over the years.
To get ready for the big clash, we’ve taken a look back at three classic matches between the two sides.
Scarlets 32-32 Ulster – Parc y Scarlets – 6 September 2014
Ulster fought back from 12 points down to earn a bonus-point draw in the 2014-15 season.
A late try from Andrew Trimble, converted by fly-half Ian Humphreys, levelled the scores right at the end after Liam Williams was sent off for two yellow cards in the second half.
Wales wing Harry Robinson had given the Scarlets a dream start after he touched down early on but Ulster responded with a score from lock Franco van der Merwe.
Dan Tuohy took Ulster ahead for the only time in the game shortly after but his side was pegged back when Rory Pitman went over on his debut for the Welsh side.
Scarlets extended their lead through Gareth Davies, making it 24-15 to Wayne Pivac’s troops at the break.
After half-time, Davies added a second score before Ulster began their comeback through a try dabbed down by full-back Louis Ludik.
Ulster continued to pressurise their opponents and made it pay late on when Trimble went over with two minutes to go.
Ulster Rugby 24-17 Scarlets – Kingspan Stadium – 2 December 2011
In 2001, Stephen Ferris led a comeback for Ulster as they battled to victory at home.
The back-rower scored one in each half for his side and there were also 14 points for fly-half Ian Humphreys as they toppled the Welsh side.
Ulster ran up 24 unanswered points to secure the victory, which saw Scarlets suffer their first defeat in the 2011-12 season.
The Welsh outfit got off to a blistering start as Sean Lamont and Viliame Iongi scored in the opening quarter to give the visitors a 10-0 lead.
But Scarlets didn’t go down without a fight after Ulster built their lead.
The team from Belfast continued to concede penalties late on, with replacement Adam Macklin sent to sinbin eight minutes before the end.
Number eight Kieran Murphy scored a late try for Ulster but it was too late to change the result.
Ulster Rugby 20-21 Scarlets – Kingspan Stadium – 21 February 2016
Michael Collins grabbed two tries for Scarlets as they battled to a tough away victory.
The full-back’s two first half scores were the cornerstone for his side’s win, along with 11 points from Aled Thomas’ boot.
Ulster actually had the lead at the break thanks to tries from Craig Gilroy and Luke Marshall, both converted by their skipper and fly-half Paddy Jackson.
The second half would become a battle between the two kickers, with Thomas narrowly edging it for the Welsh outfit.
Thomas kicked two penalties in the 10 minutes after the break before Jackson got one of his own just after the hour mark.
Scarlets held on for the final 17 minutes to keep Ulster out and ensure they got the four points.