An article syndicated by Yahoo! News reports that Prince William was subjected to multiple anti-royal chants while attending a huge game between his beloved club, Aston Villa, and Celtic.
Some of the chants were downright abhorrent. For example, a "Lizzie's in a box" chant spread across the arena at one point in the game. It can be assumed that this chant was referring to Prince William's late grandmother, Queen Elizabeth II.
Another chant, "if you hate the Royal Family, clap your hands" had nothing to do with the fixture at hand and its end result.
Mehera Bonner, the author of the syndicated article, correctly added that anti-royal sentiments are nothing new. However, we can't be sure if Prince William is truly accustomed to hearing such negative comments directed towards his family and lineage.
A terrible moment during an otherwise great day at the pitch

The events that played out on the pitch resulted in Aston Villa defeating Celtic FC 4-2 in Champions League play. William is such a die hard Aston Villa fan that the club's victory could've made the entire day better for him in retrospect. The Prince of Wales has stuck with his club through thick and thin, and he's finally been rewarded for his loyalty in recent seasons.
According to the Prince himself, William became a fan of Aston Villa after being taken to a game by someone who looked after him as a child. Experiencing football in person exposed him to a sport that others in the Royal Family usually don't pay attention to and gave him a chance to fall in love with a new discovery.
Lately, Prince William has been sharing his love of football and Aston Villa with his son, Prince George. Prince George's interest in the sport is a recent development, and his father isn't pressuring him to find a favorite team before diving into the game at a deeper level.
It's likely that Prince George will become an Aston Villa fan on his own if Prince William takes him to live games more often. However, the nasty chants directed towards William are a sign that every experience may not be safe for the youngest royals in the family just yet.
It would be a shock if Prince William let a few fans on the enemy side stop him from supporting his favorite club. Mehera Bonner claims that Celtic will be punished for its fans' actions at a later time. Shamrock Rovers, another club, was fined January 23rd after its supporters chanted “Lizzie’s in a Box" during its game against Chelsea.