I'd better start practicing right away.
2 seconds sound clip from the Play It Again, Charlie Brown movie soundboard.
You can hear this line at 00:16:06.125 in the DVD version of the movie.
Quote context
[...]
- I, your loyal and faithful companion, have arranged for your first recital.
- You have been signed up to play for the PTA benefit show.
- Really?
- Well, that's very nice, Lucy. Thank you.
- I'd better start practicing right away.
- He said thank you. He said thank you.
- He said thank you! He said thank you! He said thank you! He said thank you!
- Somehow I never quite know what's going on.
- It worked. He said thank you to me.
[...]