I Could Have Danced All Night (1964; муз. Фредерика Лоу - ст.: Alan Ja

Performed by Audrey Hepburn (dubbed by Marni Nixon), Mona Washbourne and Chorus, from the musical film "My fair Lady” (1964). The song is sung by the musical's heroine, Eliza Doolittle (Audrey), expressing her exhilaration and excitement after an impromptu dance with her tutor Henry Higgins (Rex Harrison) in the small hours of the morning.

https://en.wikipedia.org/wiki/I_Could_Have_Danced_All_Night

"I Could Have Danced All Night" 
From the musical My Fair Lady performed by Julie Andrews (Broadway) 
Audrey Hepburn (film-dubbed by:) Marni Nixon 
Published: 1956 
Writer: Alan Jay Lerner 
Composer: Frederick Loewe

...In 2004, Nixon's version finished at #17 on AFI's 100 Years...100 Songs survey of top tunes in American cinema. 

...

Bed, Bed I couldn't go to bed 
My head's to light to try to set it down 
Sleep, Sleep I couldn't sleep tonight 
Not for all the jewels in the crown 

I could have danced all night 
I could have danced all night 
And still have begged for more 
I could have spread my wings 
And done a thousand things 
I've never done before 

I'll never know 
What made it so exciting 
Why all at once, 
My heart took flight 

I only know when he 
Began to dance with me 
I could have danced danced danced! 
All night. 

It's after three now 

Don't you agree now 
She ought to be in bed 

I could have danced all night 
I could have danced all night 
And still have begged for more 
I could have spread my wings 
And done a thousand things 
I've never done before. 
I'll never know 
What made it so exciting. 
Why all at once my heart took flight. 
I only know when he 
Began to dance with me. 
I could have danced, danced danced all night! 

I understand, dear. 
It's all been grand, dear. 
But now it's time to sleep. 

I could have danced all night, 
I could have danced all night. 
And still have begged for more. 
I could have spread my wings, 
And done a thousand things 
I've never done before. 
I'll never know 
What made it so exciting. 
Why all at once my heart took flight. 
I only know when he 
Began to dance with me 
I could have danced, danced, danced 
All night!