Trebanos RFC product Tipuric will lead the Ospreys just 14 months after making his senior debut as a late replacement against Northampton Saints in the LV= Cup at the Liberty Stadium. After making two appearances last season, he has featured 12 times in the current campaign, including seven starts.
"I'm honoured to be able to captain my local team - a team I've supported since long before I was fortunate enough to be able to play for them. This is something special for me, particularly coming at such an early stage in my career," said Tipuric.
"I captained Wales U20s at the World Cup in 2009 for a couple of games, and also Trebanos when I was a boy. But this is something completely different."
Leinster are one place ahead of the Ospreys in the Magners League table and will be seeking revenge for their 17-12 defeat at the RDS in last season's inaugural Grand Final. They were also beaten by the Welsh region at the Liberty Stadium earlier this season.
With two massive Heineken Cup games to follow this weekend's game in Dublin, the Ospreys have rotated their squad and only two players, Dan Biggar and Ryan Jones, remain in the starting line-up on Friday from the Grand Final winning team of last May.
Tipuric takes over the openside duties from Marty Holah and has been given a ringing endorsement from Elite Performance Director, Andrew Hore.
"Here at the Ospreys we are all about the development of young talent and Justin is a local boy who has been given his opportunity and grabbed it with both hands. We believe that he has both the ability and the personality to become a long term captain of the Ospreys in the future," said Hore.
"He displays the characteristics and attitude that we expect from all our players coming through, and as such, is a very positive role model for all young Ospreys players, and this is a well earned reward for the progress he has made so far this season and continues to make."
Leinster welcome back their Ireland and British & Irish Lions star Luke Fitzgerald after a lengthy injury and have all their big guns in their starting line-up. It is a game that could propel either side firmly into the mix for a Play-Off place at the end of the season.
""January is traditionally a big month for the Ospreys and it's no different this time, with big games in three different competitions that will define our season. They don't come much harder in terms of the Magners League than Leinster away," admitted Ospreys Director of Coaching, Scott Johnson.
"We did pretty well out there last year, but there's no doubting they are a formidable side
Our focus this week has been about ourselves and the areas where we need to improve. After the Scarlets game it was very much about making sure the players were aware that while the scoreboard told one story, our own analysis of the game told another.
"The reality was that that performance was some way away from where we want to be, and that was backed up by the first 50 minutes against the Blues. We are still on that upwards curve and, regardless of the personnel involved on Friday night, the expectation is that we will continue improving.
"The performance against the Blues, and the changes we've made this weekend, mean that certain players have a fantastic opportunity to put their hands up if they want to be involved in some of the big games and big occasions that are coming up."
OSPREYS: Barry Davies; Nikki Walker, Sonny Parker, Ashley Beck, Richard Fussell; Dan Biggar, Rhys Webb; Duncan Jones, Huw Bennett, Craig Mitchell, Ian Gough, Ian Evans, Tom Smith, Justin Tipuric (captain), Ryan Jones
Reps: Mefin Davies, Ryan Bevington, Cai Griffiths, James Goode, Jonathan Thomas, Jamie Nutbrown, James Hook, Gareth Owen
LEINSTER: Luke Fitzgerald; Shane Horgan, Brian O'Driscoll, Gordon D'Arcy, Fergus McFadden; Jonathan Sexton, Eoin Reddan; Cian Healy, Richardt Strauss, Mike Ross, Leo Cullen (captain), Devin Toner, Dominic Ryan, Shane Jennings, Jamie Heaslip,
Reps: Jason Harris-Wright, Heinke van der Merwe, Clint Newland, Nathan Hines, Rhys Ruddock, Isaac Boss, Ian Madigan, Eoin O'Malley/Isa Nacewa