The Scarlets have lost their last two matches in the Celtic League - to Ulster and Connacht, although both of these games were away from home. At home the Scarlets have won four in a row in the competition (including a win at Wrexham against Connacht).
The Ospreys have won four of their last six matches in all competitions, including a 24-17 victory over Edinburgh Gunners at Liberty Stadium on Sunday. Away from home the Ospreys have won just once since 4 December: 22-8 at Glasgow on 27 January.
The Scarlets did the Celtic League double over the Ospreys in 2003/04, whilst the Ospreys returned the favour last season.
"The Scarlets fixture always represents one of the biggest games in our rugby calendar. There is a fierce rivalry between the teams, but we have enormous respect for what they have achieved over the years," said Ospreys Coach Lyn Jones.
"The Scarlets went through a difficult period last year, but they turned things round in reaching the Celtic Cup final and they have not looked back since. Their strength lies in their commitment and they are extremely well lead by Simon Easterby, who has developed into one the best players in the British Isles.
"We were delighted with the improvement shown against Edinburgh, but to date this season we have not fronted up against Welsh opposition, in total contrast to last season. I'm sure that there will be no quarter asked or given by either side at Stradey Park on Friday night."