Johns is the only player to win the Golden Boot twice

The 30-year-old former Test skipper and scrum-half has accepted an improved offer from the Newcastle Knights.

There has been much speculation over where Johns would finish his career, and he was reportedly offered AUS$1m to sign with New South Wales Waratahs.

Australian rugby league has seen Wendell Sailor, Mat Rogers and Lote Tuqiri switch to union in recent years.

"I woke up this morning with a clear head after what has been an agonising time weighing up whether to stay in league or accept the challenge rugby put in front of me," Johns said in a statement.

"In the end, my head told me that I should remain with rugby league. I can't wait to get back on the field next year with the Knights."

We'll never know just how good a union player he would have been and that's a shame Waratahs coach Ewen McKenzie

New South Wales chief executive office Fraser Neill said: "We gave it our best shot but it's no secret we were up against the NRL, Newcastle Knights and powerful media identities among others.

"We offered Andrew a standard NSW contract after he expressed a desire to play rugby for the Waratahs and Australia."

Neill said there had been every indication Johns would switch codes and that he would be able to release the statement announcing the signing on Friday.

"It just goes to show that a good night's sleep can work against you," said Waratahs coach Ewen McKenzie.

He added: "We'll never know just how good a union player he would have been and that's a shame but we certainly respect the enormity of the decision he had to make.

"He's an impressive man and incredible football talent who wanted to come across to our game for the challenge but in the end the rugby league offer was too good to refuse.

"I think it speaks volumes for our game that he was prepared to take the risk but now we move on."