"I know." The Doctor stopped his fiddling and looked up at Martha. "I know about Rose, and I've met Amy. Barged right through the doors without so much as a by-your-leave. Started asking questions straight away and then telling me things about the future while I was very clearly busy." He shook his head as if Amy had committed some terrible social faux pas by being concerned for him.
"Anyway, as much as it pains me to say it, I have no idea how any of this is working. In my timeline, you don't remember this happening, or if you do, you haven't told me about it. And yes, Martha Jones. You can have your old room back." He smiled. "Welcome aboard."