Billy Wilson, presumably was born around 1973, dated Piper Halliwell in her eighth grade of high school. At the homecoming dance that Piper and her sister Phoebe attended. Piper accused Phoebe of making out with him. However she defends herself, saying she was just trying to help him find a contact lens.
Billy came up in conversation when Piper and Phoebe Halliwell were fighting over the affections of their handyman, Leo Wyatt. When Prue notices how much Piper actually likes Leo, she takes Phoebe aside and talks about her being a boyfriend thief. She asked Piper the same question and she agrees with Prue, which angers Phoebe. She then tells Prue about the events that happened at homecoming, explaining that Phoebe was showing cleavage to him. They then go into war over Leo, however in the end Piper ends up marrying Leo two years later.