How is “build up” used?

In Monty Python's The Meaning of Life (1983), one line is: “Well, it's been building up to it. Has it?”

Which movie is “build up” from?

The clip at the top of this page is from Monty Python's The Meaning of Life (1983).

to become greater, more powerful or larger in number; to make sth higher or stronger than it was before; to create or develop sth

Oxford36% of films
to become greater, more powerful or larger in number
Oxford36% of films
to make sth higher or stronger than it was before
we have to build up Los Alamos,
Oxford18% of films
to create or develop sth
...if there was a reason to build up the region...
We need your showmanship to build up the suspense.

Definitions from the Oxford Advanced Learner's Dictionary, 9th edition

Well, it's been building up to it. Has it?

Said in 8 films · #1