Hilary Duff's son is "obsessed" with 'Ghostbusters'.

Hilary Duff

Hilary Duff

The 'Cinderella Story' actress has four-year-old Luca with ex-husband Mike Comrie and the little boy is such a huge fan of the recent all-female movie reboot, talk show host Ellen DeGeneres had a mini replica of the heroes' car custom made for him.

Speaking to the presenter, Hilary said: ""He wants to be a Ghostbuster this year.

"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."

Ellen then broadcast a clip of Luca singing the 'Ghostbusters' theme, before revealing the Ecto-1 vehicle she'd had made, which came complete with real steam flowing out of it.

And Hilary, 29, was overjoyed with the surprise gift.

She exclaimed: "He's going to freak out! Do I fit in this thing? It has steam coming out of it! He's going to lose his mind."

Hilary recently admitted she is so devoted to raising her son, she has put her career on hold to cherish every moment she can with Luca.

She said: "I've been very honest about this that I don't know how much time I have to put into [music]. I don't have dreams to go on a world tour anymore.

"Maybe some day, but right now, my life is so full and busy enough with the show. I love music, it's in me, it's a part of me but I look at my kid and go you're a teenager already...It's scary to think time is going by so fast and I want to be present for all of that.

"Honestly, I'm so pumped to be a soccer mom and making lunches to pack to school and not being on anybody else's schedule for a minute."