Frank Lampard has credited John Terry for his role in Aston Villa's "big uplift" in form as the ex-Chelsea team-mates prepare to meet in the Premier League.
Villa have emerged as surprise contenders for a spot in Europe after narrowly avoiding relegation last season. Dean Smith's side have won eight of their 13 matches at the start of the 2020-21 campaign, and currently sit seven points behind first-placed Liverpool with two games in hand.
Their next test will see them take on Chelsea at Stamford Bridge with Lampard set for a reunion with Terry, who has served as Smith's assistant coach since October 2018.
The former Blues duo won three Premier League titles and the Champions League together as players, while also forming part of England's 'Golden Generation' at international level.
Lampard is certain that Terry's experience at the highest level has rubbed off on Villa's squad in recent months, and told Chelsea's official website: "I am sure John has an influence because he is in my opinion one of the greatest centre-backs to have played in the Premier League and for England, and in the world for a long period of time.
"He has an absolute wealth of knowledge of the game so his input will be invaluable to Dean Smith and all the staff. Their team are working hard and you have seen a real big uplift in them, and I am sure there is a lot work behind the scenes through John and all the staff there."
The 42-year-old tactician added on the threat Villa will pose his Chelsea team on Monday night: "They obviously added to their squad in a very good way in the off season.
"They have a good manager, good coaches and a good team with very good individual players who are playing well. They are in a really good time at the moment and I am not completely surprised by it, and it will be a tough match."
The Blues slipped to eighth in the top-flight standings after losing 3-1 against Arsenal at Emirates Stadium last time out but could move back into the Champions League places if they pick up a much-needed victory over Villa.
Lampard will start preparing his side for another top of the table clash afterwards, with Manchester City set to arrive at Stamford Bridge on January 3.