Ferne announced the birth of their baby last week
The 25-year-old – who’s father to Ferne’s newborn, Sunday – was arrested in connection with the attack six days after it took place, on Saturday 22 April.
Arthur admitted to throwing the corrosive liquid at partygoers in Mangle E8 in Dalston on 17 April, but claimed he didn’t think it was acid.
He told the court he thought it was a date rape drug and took it from two men after overhearing them planning to spike a girl’s drink.
Twenty two clubbers were injured and two people were left partially blinded when the new dad then sprayed the liquid in the busy east London venue at around one o’clock in the morning.
Despite previously denying five counts of grievous bodily harm (GBH) with intent, and nine counts of actual bodily harm (ABH) against 14 people, Arthur was convicted at Wood Green Crown Court on Monday.
His co-defendant, Andre Phoenix, was also accused of helping him during the attack but was found not guilty.
Arthur is due to be sentenced on December 19.
His ex, Ferne recently welcomed their first child together after confirming her pregnancy following the news of the scary attack.
The Essex star revealed she’d given birth earlier this month by sharing an adorable photo of the little one.
Next to the sweet image, 27-year-old Ferne wrote: ‘Wellcome to the world my darling. Didn’t expect to see you a week early 🙂. I’m so in love & bursting with pride. It’s a girl’.