Falling for Figaro, a Music question

[RoseyPalm]

Hello Film Fans Help Please.
In Falling for Figaro, the lead surprises and stuns the audience with a version of "Twinkle Twinkle Little Star". I would like to find a copy of that, preferably on YouTube.
Cannot find one. Any ideas?
There are several instrumental versions. But no vocal. Whas it written for the film?

m.youtube.com/watch?v=WL42zF0Ykdk&cbrd=1

Here?

Thank you @PatriciaHolm

Have I got this right you helped Simon dodge Inspector Teal in 1930s

I did indeed! ;-) I think you are the only person to ever get that!

In the film, they said it was Mozart.

It's a piece by Mozart with the title
Variations on "Ah, vou dirai-je, maman", KV 256, originally written for piano.