The Welsh, Irish and Scottish Rugby Unions have finally agreed upon a structure for next season's newly-formed Celtic League.

The agreement, which was reached on Tuesday, confirms that nine Welsh clubs, four Irish provinces and two Scottish professional teams have committed to the competition.

A fixture list has also been complied. The action kicks-off on the weekend of Saturday 18 August with the final on Saturday 15 December.

The competition will be played in two conferences before the knockout stages.

The fixture list will not be released until consultation with relevant commercial bodies.

An announcement on the league's sponsor is also expected soon.

"I am convinced the Celtic League can only be good for the rugby development of our three countries," said Syd Millar, who chaired Tuesday's meeting.

"That, in turn, can only be beneficial for the overall strength of northern hemisphere rugby."

The Celtic League will run for an initial period of three years.

Teams involved in the first year are Bridgend, Caerphilly, Cardiff, Ebbw Vale, Llanelli, Neath, Newport, Pontypridd and Swansea from Wales; Connacht, Leinster, Munster and Ulster from Ireland; and Edinburgh Reivers and Glasgow Caledonians from Scotland.