Nodding slowly he wondered what the TARDIS looked like with the remodel. Must be in a better shape than it was when he was last in the TARDIS. "Ah. And now I guess you been giving the TARDIS a new nickname?" He asked curiously, smirking a little. 
This was a bit amusing to Arwen already. The Doctor complementing the TARDIS while having a boyfriend. This had to being going through the Time Lord's mind.