The club's record goalscorer, who retired in 2006, had been mooted as a possible successor to Sam Allardyce before Keegan made his sensational return to St James' Park on Wednesday.

Magpies fans are still dreaming of the double-team of Geordie legends - and Shearer refused to rule out the possibility.

The former England captain said on BBC1: "First and foremost, I'm not so sure he's thought about it. He's his own man.

"If he were to ring me and ask to speak to me, I would certainly speak to him. I'd be foolish not to.

"I was never really a serious possibility (for the manager's job) because they were looking for experience."

However, he added: "I haven't really seen myself as a number two."

Shearer is still keen to manage Newcastle at some stage, but hopes Keegan, who previously bossed United from 1992-97, is successful enough to delay that eventuality for some time to come.

"It remains an ambition to manage it some day - when that will be I don't know," he continued.

"I hope and pray that he (Keegan) does well because I'm a fan at the end of the day.

"The place will be rocking.

"The fans have what they want. They want entertainment, passion and commitment, and they haven't seen it of late.

"They will go forward and score goals and I'm sure they will concede a few.

"I was surprised (by the appointment) but Newcastle have that power in his (Keegan's) heart. He wants to do so well for them.

"He failed to win a trophy for them last time but you can bet your bottom dollar he will try to win one this time."

Former Newcastle defender Warren Barton believes the return of Keegan will make 2007-08 "a season to remember".

He said: "It's a season to remember already - he's come back.

"A UEFA Cup spot is a possibility. If I was in the dressing room and he walked in, that would give me a lift.

"The players have got to respond - there is quality in that team."

Former Magpies and England winger Chris Waddle believes the return of Keegan will allow United to once again compete for some of the game's best talent.

"Players look at wages but they like to play for a manager who has got a lot of passion, a lot of desire, and Kevin Keegan is a very big name in the world of football," he told BBC Radio Newcastle.

"He's got to the end of the month to get some players in, I'm sure there will be a lot of activity."

Stylish winger David Ginola epitomised the football favoured by Keegan in his first spell on Tyneside.

The Frenchman believes his former boss, driven by a determination to make up for the narrow failure to win the Premier League in 1995-96, will end the Magpies' long wait for silverware.

"Newcastle haven't won anything for many years and they are desperate to win something. I'm pretty sure he's the guy who will bring success to Newcastle," Ginola said.