Ex-Toon skipper Shearer is the club's all-time top-scorer with 206 in all competitions from 1996-2006 and has taken over for the final eight league games of the season, with United currently two points adrift of safety.
However, fellow Geordie Waddle believes the former England captain's stock on Tyneside will diminish should he fail to stop his hometown team from an unimaginable relegation to the Championship.
“If he keeps them up, he will be hailed as the best thing since Alex Ferguson," he said. "Yet if they go down, people will say Alan Shearer was a great footballer but could not manage to save his life.
“That, of course, would be grossly unfair. Nobody should be judged on eight games. But Alan has put himself under immense pressure by taking on this job at this stage of the season, with Newcastle where they are in the table. That is for sure.
“The only way he can win is by keeping the club in the Premier League.”
And Waddle - who made 62 appearances for his country - alluded to new film The Damned United, which chronicles Brian Clough’s ill fated spell as manager of Leeds United, in his warning to Shearer.
“Never mind the film about Brian Clough’s 44 days at Leeds," he said. "They will be making a movie about Alan’s eight games in charge of Newcastle if they end up being relegated this term!"
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