I didn't know that. [He makes a soft, contented sound at the fingers in his hair (he likes fingers in his hair, and leans his head sideways against her shoulder instead so he can watch the screen and still have the contact. He's more or less forgotten about the pheromones, for the moment.]
He regenerates. Literally changes every cell in his body and becomes a completely new man. The other version who was here - tall, skinny, floppy hair, brown suit and converses - that was the next regeneration after this one. But this was my Doctor. The one who saved me, taught me to do good.