"Sometimes I used to kiss him on the cheek," the gymnast said. "It's a little strange."
Biles has spoken about her love for Efron before, so much so that Ellen Degeneres once gave Biles a leotard with Efron's face on it.
On Monday Efron tweeted his support for Biles as she competes in the Olympics in Rio.
"So phenomenal a skill's named after her. Congrats on sticking the Biles and qualifying for the finals," he tweeted to her.
So far Biles has nabbed a gold medal with Team USA in the women's team all-around competition. She's going for the gold again in Thursday's individual all-around competition.