Stuart and some of his coaching assistants from the Canberra Raiders arrived in Oita on Tuesday and joined the English squad straight away, upon invitation from their coach Eddie Jones.

Stuart is officially there in an observational role and Cheika questioned on Monday why an Australian rugby league coach would join a team from another country and another code who are preparing for their biggest game in four years.

Cheika suggested the English players would find the situation "weird".

However, England assistant coach John Mitchell said Stuart's presence was invaluable because of his very recent experience of another big stage - the NRL grand final nine days ago, when the Raiders lost to the Sydney Roosters.

"They've just recently played in one of the major rugby league competitions in the world. You'd be stupid if you weren't able to gain something from that," Mitchell said.

"Ricky is not the only coach from rugby league or any other sport that has come in.

"We have them on a regular basis and so at the end of the day we want to see what we are doing that can be improved and we like to learn off others and that's the great opportunity we have."

Australian Associated Press