A day after offloading Matej Vydra to Burnley, Derby have now confirmed that a deal has been struck with the Tractor Boys for Waghorn's signature.
On his latest signing, Lampard told the club's official website: "I'm delighted to see Martyn Waghorn become a Derby County player - I think this is a big signing for us.
"He has been sought-after all summer and we've managed to bring him here, which is fantastic. We sold the club to him and, importantly, he wanted to come here and that's the sort of player that I want in the squad.
"Martyn has many great qualities and he has been pretty prolific over the last few years in front of goal. He is a real all-round striker and last year we saw not only could he score goals in the Championship but create them as well."
Waghorn has scored a total of 93 goals in 314 appearances during a senior career that started at Sunderland in 2007.