How do they (blockbuster) do those commercials were?!

Question: they take parts of older movies(alien) and change it for there commericial... please best in detail gets 10 points

---

---

Answers: they take parts of older movies(alien) and change it for there commericial... please best in detail gets 10 points

---

---

They film the actor against a green screen saying the lines and patch it in to the original footage.

My guess is it also involves some CGI work (Computer Generated Image).

---

---

---