Frank Lampard will be visiting old enemies and even older friends as he takes his Derby County side to Millwall on Saturday.
Lampard's playing career saw him turn out for two of the Lions' biggest local rivals, West Ham and Chelsea, while the Rams boss played in the same school team as Millwall manager Neil Harris when they grew up in Essex.
Millwall have two draws to their name so far in the Sky Bet Championship this season, having seen a 2-0 lead slip on the opening game at home to Middlesbrough who scored two late goals including a 97th minute equaliser, then being held 0-0 at Blackburn Rovers last weekend.
And with both sides looking to build on midweek Carabao Cup wins, Millwall's having been on penalties at home to Gillingham, Lampard is expecting a tough encounter at the New Den.
He said: "Millwall dominated the vast majority of their game with Middlesbrough and it was a game they should have won, while Blackburn is a tough place to go and they got a draw, so they're a very good team and effective at what they do.
"They're a very strong team with a strong crowd behind them at home, so we go there with utmost understanding of what we're going into.
"We have to match them physically, as that element of their game is there to be seen for everyone, as is the direct nature of their game at times and they don't shy away from that, nor should they after some of the performances they put in last season.
"But as well as matching them we have to be big enough and brave enough to bring our game to the New Den and try and improve with the ball, because if we are going to win this game it's not just about competing, we have to be good on the ball too."
Lampard and Harris both played for the football team at Brentwood School in Essex, and the Rams boss has great respect for what his former team-mate has achieved.
He said: "Neil's a little bit older than me but I managed to play up a year in the higher age group so we played alongside each other a lot, although our paths haven't crossed too often since.
"He's had a fantastic career, and the issues he had at different times too show not just what a player he was but the man that he is too, and even though we were only boys it was evident he had something about him to not only have a great football career which he did, but to also then become the manager he's very quickly become.
"So the team is an image of him. He scored lots of goals and they have that in them - to talk them down and say they're a standard long ball team is wrong, they have a way of playing but they also have quality that can get them goals to win games."
Lampard added he expects a lively welcome from the home faithful given his loyalties as a player, commenting: "I spent 13 years at Chelsea who are big rivals and obviously West Ham are huge rivals too, but it's part of the territory of playing at any clubs where you have arch rivals and you have to feed off that, negate the hostile atmosphere and use it to our advantage."
The Rams boss says Tom Huddlestone and David Nugent could be fit to play a part on Saturday providing the risk is low of their injuries returning, while Curtis Davies has returned to training and it is hoped he will be fit to return ahead of the Preston game on August 25.