Joseph Parker's heavyweight unification bout with Anthony Joshua in Cardiff is just over a month away, and the pair have been putting in the hours in the build-up to the Principality Stadium bout on March 31.New Zealander Parker, the current Olympic champion having won gold at the Rio games back in 2016, will meet the London 2012 champion Joshua in a heavyweight battle.Parker recently recruited Frenchman Tony Yoka to become his sparring partner heading into the showdown in the Welsh capital.Parker, aged 26, is the current holder of the WBO heavyweight belt, though, will be aiming to unify the division should he defeat Joshua.His decision to bring in Yoka into his backroom staff will see Parker pick the brains of his new sparring partner, who formally worked alongside Joshua.However, Parker and Yoka as a pair have history together in the sport, which dates back to 2010.Yoka, who has now made his way into professional boxing after impressing on the amateur circuit for the last few years, a semi-professional career that went hand-in-hand with his sparring responsibilities in Joshua's camp.Indeed, Yoka actually found himself victorious against Parker eight years ago, way back in 2010 - during a world amateur bout between the pair.The two fighters met at the World Youth Tournament as 17-year-old up-and-coming teenage boxers, with Yoka defeating Parker on his route to being crowned champion of the event.

Yoka comfortably claimed the bout, and would go onto have a fruitful career as an amateur, prior to being signed up by Hayemaker-Ringstar, making his professional debut in June last year.

Meanwhile, Parker believes he can surprise Joshua when the two lock horns in the heavyweight bout.

He told ESPN: "With a lot of his fights, he's finished off his opponents with a combination of punches, not just one punch, but everyone has one-punch knockout [power] if they land the right punch at the right time.

"My focus is myself and my training. If they are looking past me, they will be in for a surprise."