LaCaze, who was celebrating her 25th birthday, waved the Australian flag and joined in with the popstar's backing dancers during "The Loco-Motion".
She told Channel 10: "I just wanted a little bit of claim to fame. I wanted a little bit of TV time, I am turning 25, so why not.
"I'm the one who worries about the consequences before taking the chance of doing something a little bit rebellious, but I thought, 'It's my 25th birthday'.
"I don't know, I find 25 a number where you're becoming an adult really, and I thought maybe one more childish act was in me."
LaCaze finished fifth in the 3000m steeplechase event at Hampden Park last week.