The 22-year old will arrive in Wales for pre-season after putting pen-to-paper on a contract which runs until the end of the 2016/17 season.
Born in Pretoria, Bernardo came through the ranks at Eastern Province Kings, representing them at age-grade level before playing in both the Vodacom and Currie Cup competitions. In 2013 he graduated to Super Rugby with the Southern Kings, playing in 10 games for the tournament newcomers. This season he has again been featuring for Eastern Province, but the Ospreys have reached agreement with his club to enable his release in time to enable him to spend a full pre-season with his new team.
He will add a physical presence to the Ospreys second row options, standing 1.99m tall and weighing in at 113kg, bringing the traditional hard nosed South African approach to forward play to the Liberty Stadium.
Speaking about his move to the Ospreys, Bernardo said:
"This is a fantastic opportunity for me, personally and professionally, and I'm really excited about arriving in Wales this summer. The Ospreys are a great team used to competing at the top end of the PRO12, with some great players, and I'm looking forward to being a part of a young and talented squad there.
"It's a big challenge for me, but I can't wait to get started. Hopefully I'll be able to make a big impression and help the team to more success, domestically and in European competition."
Bernardo is the fourth new face confirmed for next season following the announcement earlier this year of Fiji centre Josh Matavesi from Worcester, Welsh international full-back Dan Evans and his Dragons team-mate, hooker Sam Parry.
"Rynier is an exciting addition to our squad and something of a coup for the Ospreys" said Andy Lloyd, Rugby Operations Manager at the Ospreys.
"He is highly respected in his home country and comes with a strong reputation as a traditional second-row who tackles well, hits rucks, and has the all-round physical edge that you expect from a South African in that position. It's a really positive signing for us.
"As well as being impressed by what we've seen of him, we spoke to a lot of people whose opinion we value about his character, on and off the field, and what he will bring to our environment. He's a big man who thrives on the unglamorous side of the game and will do the work that doesn't get seen, allowing our back row boys and the backs to express themselves.
"He's a young man who has chosen to come here for the challenge instead of staying in South Africa where our feedback tells us he is extremely highly regarded as a potential future Springbok. That kind of attitude is exactly what we want in an Osprey.
"Bringing in Rynier means that we have increased options available to us for next season and we won't have to over rely on the likes of James King and Tyler Ardron in the second row. They are great club men who will do any job asked of them, but we see them primarily as back rowers.
"It's important that we have additional options in the squad, not only to keep the likes of Alun Wyn and Lloyd Peers on their toes, but to also support the next tier of locks coming through the system. We know that we have people like Rhodri Hughes, Rory Thornton, Adam Beard and Matthew Dodd on the pathway, so there is a lot of talent coming through, but development isn't just about chucking a lot of youngsters in too early, it's about allowing them to play alongside hard-nosed professional players. Rynier definitely fits the bill."
As well as the four confirmed new signings, the Ospreys have also secured the services of a number of key players beyond the end of the current campaign. Alun Wyn Jones, Sam Lewis, Ashley Beck, Eli Walker, Jonathan Spratt, Ben John, Ryan Bevington and Dmitri Arhip have all signed new contracts in 2014
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