The song “Come from the Heart” (1987) by Susanna Clark and Richard Leigh contains the lyrics:
 
“Sing like no one is listening.
Love like you’ve never been hurt.
Dance like nobody’s watching,
and live like it’s heaven on earth.”
       
“I danced like no one was watching, but someone was watching and he thought I was having a seizure and called an ambulance” is a jocular variation that has been printed on many images. “I attempted to ‘dance like no one was watching’, but someone was watching, and mistook my dancing for a seizure and called an ambulance” was posted on Twitter by The Doctor on September 20, 2009.
 
“Dance like no one is watching. Because they are not. They’re checking their phones” is a related saying.
         
   
Twitter
The Doctor
@TheDrDon
I attempted to ‘dance like no one was watching’, but someone was watching, and mistook my dancing for a seizure and called an ambulance.
2:37 PM · Sep 20, 2009·Twitter Web Client
   
Twitter
Jodee Wedgeworth
@Jodee81
attempted to ‘dance like no one was watching’, but someone happened to be watching, mistook my dancing for a seizure & called an ambulance.
12:21 AM · Sep 25, 2009·Twitter Web Client
   
Twitter
Gilbert
@jeffagibson
I attempted to ‘dance like no one was watching’, but someone seen me, and mistook my dancing for a seizure and called an ambulance.
7:50 AM · Oct 6, 2009·Twitter Web Client
   
Twitter
Valerie Grella
@bgbrwneyesNY
I attempted to ‘dance like no one was watching’ but someone happened to be watching & mistook my dancing for a seizure & called an ambulance
11:58 AM · Oct 14, 2009·Twitter Web Client
     
Facebook
Sun Gazing
June 13, 2014 at 4:30 AM ·
I danced like no one was watching but someone was watching, thought I was having a seizure and called an ambulance.
Follow Sun Gazing
— with Julie Ann Joyner.
 
Facebook
Steve LeMay
March 10, 2020 at 11:35 AM ·
I danced like no one was watching but someone was watching; thought I was having a seizure and called an ambulance.
 
Twitter
Owais siddique
@OwaisCraziya
I danced like no one was watching but someone was watching and he thought i was having a seizure and called and ambulance….
1:38 AM · Aug 5, 2020·Twitter for Android
 
Twitter
Tom Pickering
@maspick
I danced like no one was watching, but someone was watching, thought I was having a seizure, and called for an ambulance! d;¬{D
#TomsDailyQuips
11:52 AM · Sep 3, 2020·Twitter Web App