You tell 'em, Neville!
He sported his signature green and black Slytherin cloak.
"Agings a b----," Felton, 32, wrote.
And fellow former costar, Matthew Lewis, who played Neville Longbottom, had something to say to that statement.
"Speak for yourself lad," Lewis, 30, teasingly wrote back.
According to E! News, the two have stayed close friends since the final "Harry Potter" film wrapped nearly a decade ago and have even had several meet-ups over the years.
In August 2018, the two reunited with former co-star Emma Watson, who played Hermione Granger in the franchise.