Mark, a former member of NCT, wears a shirt featuring the Confederate flag as he signs an autograph. Captured from an online community

Mark, a former NCT member who recently launched a solo career, apologized Tuesday in a statement released by his new label after photos showed him wearing a T-shirt featuring the Confederate flag.

The photo drew immediate backlash from international fans who cited the flag's association with white supremacy and racism.

The criticism highlighted an early test of cultural awareness for the newly independent solo artist. The incident's timing, close to June 19, amplified the backlash — the date is also known as Juneteenth, a U.S. federal holiday commemorating the end of slavery.

The shirt featured the flag of the Confederacy, which was formed in 1861 when 11 Southern states seceded from the U.S. to preserve slavery.