Lauren Bacall for "To Have and Have Not" (1944), Bacall was so nervous that, to minimize her quivering, she pressed her chin against her chest, faced the camera, and tilted her eyes upward. This effect, which came to be known as "The Look", became another Bacall trademark, along with her sultry voice. Bacall's character in the film used Slim Hawks' nickname "Slim", and Bogart used Howard Hawks' nickname "Steve". The on-set chemistry between the two was immediate according to Bacall. She and Bogart (who was married at the time to Mayo Methot) began a romantic relationship several weeks into shooting. Bacall's role
What Love Is Made Of three minutes and fifty-five seconds (3:55), "What Love Is Made Of" is an uptempo dance and house track that has been described as "rave-y" and "trance-y". Its instrumentation contains the sounds of pianos and synthesizers. Jordan Sargent of "Spin" observed that it continued the musical style first introduced in Katy's 2012 extended play (EP), "Danger EP", which was "straight-forward house". Idolator's Sam Lansky compared her performance in the song to recording artist Siobhán Donaghy. Critical response to "What Love Is Made Of" was generally positive: most critics noted Katy's vocal performance and commended its sound. Siân Rowe from "NME" was