The Portugal forward had his second stint at United brought to an early conclusion last month after an inflammatory interview with Piers Morgan, in which he revealed his unhappiness with the Red Devils and club manager Erik ten Hag.

Ronaldo's contract with the Premier League giant was terminated shortly after the start of the World Cup, at which he scored one goal and was reduced to the role of substitute for Portugal's two knockout games.

Having revealed he previously rejected a move to the Saudi Pro League, Ronaldo had been strongly linked with Al Nassr since leaving Old Trafford.

While Ronaldo denied a deal had been agreed earlier this month, Al Nassr sporting director Marcelo Salazar said the club would remain patient in its attempts to take him to Riyadh – and that approach likely has paid off.

Widespread reports claim Ronaldo had agreed a two-and-a-half-year deal with Al Nassr, where it is suggested he will earn more than £60million ($A106m) per season.

Those reports also claim Ronaldo had already undergone one part of his medical.

Ronaldo's move will bring the curtain down on his remarkable stint at the top of the European game.

The 37-year-old could potentially be available to make his Al Nassr debut on Friday 6 January (AEDT), when Rudi Garcia's side hosts Al Ta'ee.

Al Nassr is second in the Saudi Pro League after 10 games, just two points adrift of leader Al Shabab.