Eliza Doolittle admitted it was difficult playing to an empty London jazz club while fans logged in online.
In a Facebook first, the star performed many of her hits at Ronnie Scott's to a virtual audience - estimated to be in the thousands.
"I am honoured that this is the first UK live gig on Facebook, I can't believe it hasn't been done before," she said before the event.
"I did a live stream in New York before, and it's kind of weird not being able to talk back to anyone, not hearing the applause, not seeing any faces and not knowing if it is all going well or not."
The singer - whose real name is Eliza Caird - predicted digital gigs could be the future.
"I definitely see a future on YouTube. People already put up covers and songs on there, so why not do it live? It gives the artist an edge then," she added.