"Why does Millie Bobby Brown actually look like she's in her 30s," one fan wrote.
"Millie Bobby Brown is 15 years old. Everyone who is responsible for this look needs to get fired," said another.
While Millie's gorgeous Louis Vuitton gown/pantsuit was stunning, it was accessorised with an Essential Lines necklace with diamonds set in platinum, an Etincelle de Cartier ring clustred with diamonds and extremely grown-up heels...
"I don't see a 15-year-old here. She looks like she's an adult cast member crashing the teen photo," another fan wrote on Twitter.
"Millie Bobby Brown went from a baby eating waffles to looking like she's got two kids and a mortgage," comedian Travon Free said.
Another fan added, "When Millie Bobby Brown looks more Meryl Streep than Meryl Streep does.
The star turns sixteen in a few weeks.
