Johann Muller has won 23 caps for the Springboks
David Humphreys says Ulster have secured a world-class forward in South African Johann Muller.
The 29-year-old Muller, capped 23 times by the Springboks, has signed a two-year contract with the Irish province.
Muller won his first cap against Scotland in 2006 and played in the 2007 Rugby World Cup in France.
"Johann will add a hard edge to a pack that has become more competitive over the past few months," said Humphreys, Ulster's Director of Rugby Operations.
"A lot has been spoken about the potential and the youth of this current Ulster squad.
"We are committed to signing foreign players who, like Johann, have the ability to improve our performances on the pitch and also help develop these young players into Ulster and Ireland stars of the next decade."
Muller currently plays for the Natal Sharks and his final appearance for South Africa was against the British and Irish Lions last summer.
Muller will arrive in the province at the end of the 2010 Super 14 competition and join up with the Ulster squad on 1 July.