- Oh, didn't I tell you I've got a brain the size of a planet?
- Oh, yeah.

5 seconds sound clip from The Hitchhiker's Guide to the Galaxy (1981) - Episode 5 sitcom.

You can hear this line at 00:26:02.080 in the Blu-ray version of the TV Series.

Quote context

[...]

- Will you shut up and listen. This time, there's going to be excitement and adventure, and really wild things.

- Sounds awful. I suppose you want me to help you to get into this spaceship and open the door for you.

- What?

- Er, yeah.

- Well, I wish you'd just tell me, rather than try to engage my enthusiasm, because I haven't got one.

- Abraca-diodular-servo-systems.

- How do you do that, Marvin?

- Oh, didn't I tell you I've got a brain the size of a planet?

- Oh, yeah.

- Hey, Zaph, come and have a look at this.

- Hey! Weird! It's so black. Everything in it is just totally black.

- Well, this is very pretty, I must say.

- Yeah, I like a change of scene.

- Hey! This is one ace, wonderful ship, eh, Ford?

- Yeah. Pity it doesn't seem to work, isn't it?

[...]