The two men will be in opposing dugouts at the Stadium of Light on Wednesday night as promoted Norwich attempt to complete a double over O'Neill's Black Cats.
But it will be a reunion for the pair, who worked together during O'Neill's reign at Celtic after he had plied his trade at Wycombe, Norwich and Leicester.
Lambert started in Scotland with Livingston before also making his way to Wycombe, then Colchester, before arriving at Carrow Road - and O'Neill admits that learning process is invaluable.
He said: "My own view is that I think it's a great help, I do, and maybe it's because that was the approach I took.
"Now don't get me wrong, if somebody in the Premier League - or what was called the first division in those days - had taken a chance with me when I was looking around at the time, then I am sure I would have grabbed it.
"But deep down, I am pleased that this is the way I went because I learnt an awful lot.
"Paul has taken that route and so far, it has worked out pretty well for him.
"Of course, if somebody wants to, if you are a big enough player and Real Madrid want you as your first job, you don't turn it down.
"But essentially, there is nothing wrong with going and working up through the leagues."
O'Neill's was in charge at Norwich only briefly, but had two spells with the club as a player and retains an enormous affection for them.
He said with a smile: "It's a great football club, really fine. The fact that it's probably closer to Holland than it is to London is, I think, very endearing."
Sunderland lost 2-1 in Norfolk at the end of September, but are a very different proposition since the new manager's arrival, and welcome Lambert and his players to Wearside having lost just two of their 10 games to date under him in all competitions.
However, O'Neill is having to contend with a fresh injury crisis which has robbed him of the services of defenders Wes Brown, Titus Bramble and Matt Kilgallon, midfielder David Vaughan - and perhaps skipper Lee Cattermole too - as well as striker Nicklas Bendtner.
To that end, he spent the final day of the winter transfer window busily attempting to bolster his squad, and doing so in the shape of Manchester City full-back Wayne Bridge and former Liverpool defender Sotirios Kyrgiakos.
Bridge, who has just one senior appearance to his name all season, went straight into the squad for tonight's game, and could hardly have been more delighted.
He told SAFC TV: "I have looked at the fixtures and this month's quite busy with a game every few days. That's going to be good for me."
