Ellis works with the French national team, who he helped to Six Nations success this year, and Gloucester.

A former rugby league player with Cas, Keighley, Doncaster, Batley and in Australia, he has undertaken to work with the Tigers players one day a week.

Chief executive Richard Wright said: "Dave offered to help and we were very happy to accept."

Ellis will spend more time with Castleford, bottom of the Super League and still looking for their first win. once the domestic rugby union season ends

After hanging up his boots, Ellis had a successful spell as coach of French club Villeneuve before working as assistant coach role at Paris St Germain when they entered Super League.

When the Paris venture folded, he began working in union and has gone from strength to strength.

Wright added: "We are working very hard behind the scenes to make sure that the Tigers turn things around and climb the Super League.

"I am sure that Dave will be a big help to (caretaker coach) Gary Mercer and (assistant) Brad Harrington."