Songfacts®:

• This Is Acting comprises Sia compositions salvaged from the figurative dumpster after being discarded by various A-list stars. This song was a Beyoncé reject that the Aussie wrote when she was in New York. She told Rolling Stone: "We did that in the Hamptons session we did years ago for the most recent album she did. I got 'Pretty Hurts' from that album, but originally I wrote 25 songs for it while we were in the Hamptons and one made the record. Isn't that amazing?"
• Sia described the experience of writing for Beyoncé, as being "very Frankenstein," as according to the Aussie, Queen B likes to mix bits and pieces from various songwriters. "In the end, she had maybe 25 songs of mine on hold," Sia said, "and I was very excited to get a couple of them back."
• The lyrics were inspired by the allegorical poem "Footprints"
  
  I saw only two footprints in the sand
  Thought you'd abandoned me
  Let go of my hand, but you were carrying me
  Carrying me to safety.
  
  The original poem, whose authorship is disputed, dates back to the nineteenth century. It describes a person walking on a beach with God with the trail representing various stages of their life. Two sets of footprints are left in the sand behind them, but from time to time they dwindle to one. This is because God was carrying the person during the lowest and most hopeless moments of their life.
  
  Leona Lewis had a #2 hit in the UK with her version of the poem, "Footprints In The Sand."