Both players signed one-year deals on Thursday.

Smith, born and raised in South Africa, boasts more than eight years of Super Rugby experience after making his debut for the Western Force in 2012, spending five seasons with the Brumbies, two at the Queensland Reds and one with the Melbourne Rebels.

He also has played abroad after spending time in Japan with stints at Toyota Verblitz.

Smith's signing with the Waratahs will give him the opportunity to become the first player to represent all five Australian Super Rugby sides and will be aligned with the Hunter Wildfires in the Shute Shield.

The veteran prop is excited for the next chapter in his career.

"DC (Darren Coleman) called me and asked if I was interested in playing for the Waratahs and told me I had a lot to offer the group," Smith said.

"Playing for Waratahs is a massive opportunity. It's the biggest team in Australia."

Head coach Coleman said it was no secret the Waratahs struggled at scrum time during this year's winless campaign.

"So with the few spots we needed to fill, size, experience and an aggressive nature were key aspects we were looking for and Ruan ticks all those boxes," Coleman said.

Holz grew up in Lightning Ridge, a small outback town in north-western NSW, and later attended The Kings school in Parramatta, playing GPS and Australian Barbarians in 2018.

He played first grade colts in 2019 straight out of high school at Eastern Suburbs in the Shute Shield, before making his first-grade debut for the club as 20-year-old in 2020 under current Waratahs forwards coach Pauli Taumoepeau.

Strong showings in the Shute Shield prompted the Brumbies to offer Holtz a contract for their 2021 Super Rugby campaign, in which he made his debut in round four against the Reds.

The proud New South Welshman is excited at the prospect of fulfilling a childhood dream of playing for the Waratahs.

"Growing up in country NSW and playing rugby as kid, the Waratahs has always been the team I supported, so I'm really grateful to get the opportunity to hopefully wear the sky blue," Holtz said.

Taumoepeau is looking forward to having another big body to reinforce his front-row stocks.

"What Archer brings naturally is a really big body, and he knows how to use it effectively," Taumoepeau said.

"He's a beast in the scrum and had a lot of success there for us at Easts and brings a real presence in defence."

Australian Associated Press