George Pimentel / WireImage 1 / 9
George Pimentel / WireImage 1 / 9

Why so sad, Justin?

Justin Bieber looked nothing short of miserable as he posed for photos at a private estate in Toronto on April 30 at what is believed to be an engagement party for his father, Jeremy Bieber.

One day after he shaved off his controversial dreadlocks, the Biebs, 22, sported a sad face in a series of photos with Jeremy, who proposed to girlfriend Chelsea Rebelo in February, as well as a tiger and guests at the bizarre bash.

The party was billed as a private VIP Art Show and Nyotaimori Celebrating Life Love And Art and held at the private residence of Dr. Rita Kilislian and Andy Curnew, but both DailyMail.com and TMZ reported that it doubled as an engagement party for Justin's father, 40, and Chelsea, 28.

The bizarre event featured guests dressed as superheroes including Wonder Woman, Iron Man, a female Captain America and Batman, among other pop culture characters.

Yet none of the costumed revelers could seem to turn Justin's frown upside down.

The "Sorry" singer even looked unhappy when he posed with party guest and former heavyweight champion Lennox Lewis.

So what was wrong? Justin, who was on a break from his "Purpose" world tour, hinted that he wasn't feeling well in a selfie posted earlier in the day. "Soooooo hungover I feel like s---," he captioned the snapshot, in which he also showed off his new buzz cut.

Or perhaps he felt burned by his little brother Jaxon Bieber? Justin shared a brief Instagram video of the 6-year-old also sporting a buzz cut in which the bot tells the camera, "Justin, you copy me. But I look better than you."

Justin later posted a photo of himself petting the equally miserable-looking tiger at the bash.

TMZ also shared video of Justin playing the piano at one point in the evening. He also half-heartedly appeared on the dance floor with a crowd of women.