The painter bit his lip and walked over, cup in hand, to the picture. "I shall stay with the real Dorian," he said, sadly.
"Is it the real Dorian?" cried the original of the portrait, strolling across to him. "Am I really like that?"
"Yes; you are just like that."
"How wonderful, Basil!"
"At least you are like it in appearance. But it will never alter," sighed Hallward. "That is something."

– Oscar Wilde

The Picture of Dorian Gray, Chapter 2. Basil calls his portrait of Dorian the "real" Dorian. And that exactly what it turns out to be. Dorian continues to keep the appearance of youth while the portrait changes to reflect his inner soul – in keeping with his Faustian deal to trade his soul for eternal youth.