The Blues legend took over at Pride Park this summer in his first managerial role. And the Englishman hasn't been shy signing players from his former club.
This time it is defender Fikayo Tomori, who has signed on a season-long loan deal.
Tomori joins Mason Mount as Chelsea loanees now plying their trade with the Championship club.
Speaking to the Derby website about his new signing, Lampard said: "We're really pleased to bring Fikayo in to provide us with another defensive option.
"He fits the profile for us; he is a talented young player and he has already got experience in the Championship from his loans at Brighton and Hull.
"I know him from my connections at Chelsea and, like with the other players we have brought in on loan this summer, I am confident we can be good for them and they can be good for us."