The host was chatting with Duff about 4-year-old Luca when the actress revealed that her son is a huge Ghostbusters fan.
"He wants to be a Ghostbuster this year," Duff said of Luca's Halloween plans. "He's obsessed with Ghostbusters, obsessed with Slimer. He learned the whole song...it's so good. He's so serious about it, you guys."
DeGeneres then shared a clip of Luca singing the Ghostbusters theme song, and the enthusiastic tot absolutely nailed it!
DeGeneres then gifted Duff with a custom Ecto-1 car for her son, the mini-vehicle coming complete with an ECTO-LUCA license plate and real steam.
"He's going to freak out!" Duff said after seeing the car. "Do I fit in this thing? It has steam coming out of it! He's going to lose his mind."
See the host's gift in the clip above!