United's stars, past and present, have welcomed 'home' the Portuguese great after a 12-year absence following the details of his sensational move from Juventus were revealed on Friday.

'CR7' will become a United player again after leaving for Real Madrid in 2009, with his transfer from the Serie A giants subject to the agreement of personal terms, securing a visa and undergoing a medical.

Ronaldo's former teammate Ferdinand opened the lid on how he believes the move happened.

"Cristiano and Sir Alex Ferguson have got a bond," Ferdinand said on his YouTube channel.

"Very few players get to have that in their career with a manager. Sir Alex played a massive part.

"There was no way Cristiano was coming to Man United without speaking to Sir Alex. Simple as that."

Ferdinand praised the United board for moving quickly after neighbours Manchester City had appeared to be the 36-year-old's likely destination.

He said: "Wow! The pendulum has swung. What a 24 hours. Man United have done what they needed to do.

"The Man United hierarchy ... performed perfectly at every step. There was no looking over their shoulder, no hesitancy about it.'

Ferdinand said Ronaldo's arrival re-establishes United as the "hottest ticket" in world football.

He added: "You can't put into words what it's going to do for the dressing room and the fanbase. He'll get you 25-30 goals this season. That's what he does.

"What he can do for Mason Greenwood, Marcus Rashford and Jadon Sancho alone is worth bringing. He will show them what an A-lister, genuine superstar and an absolute obsessive professional lives and breathes on a daily basis."

United players took to social media to welcome Ronaldo back to the club he joined in 2003 and where he spent six trophy-laden seasons.

Bruno Fernandes, who reportedly spoke to his Portugal teammate about returning to United, tweeted: "'Agent Bruno'?" alongside emojis of a briefcase and a face with tears of joy.

He also added a cartoon of himself as a youngster watching Ronaldo alongside the caption "Never stop dreaming...".

United's summer signing Jadon Sancho and fellow England internationals Marcus Rashford and Jesse Lingard were among a host of current United players to tweet about Ronaldo.

Roy Keane, who was United captain when the club first signed Ronaldo, wrote on Instagram: "Welcome back Cristiano", while Edwin van der Sar posted on his account: "How are you feeling @manchesterunited fans? Always dreamt but never expected that it would happen! Welcome back in Manchester @cristiano".

Gary Neville, another former teammate, told Sky Sports: "This news gives me more hope that United could have a great season because this is one of the most special players who has ever played the game of football."

Australian Associated Press