At the very end of "The Big Bang", when Eleven, Amy, and Rory are in the TARDIS, the TARDIS gets a phone call. Eleven answers and it's (allegedly) from the Queen (we only hear Eleven's side of the conversation), asking him to deal with a situation on "the Orient Express...in space!"
Listen closely when he's talking to himself in his berth. The "A mummy no-one else can see" line as well as the next line in that "side" of the converation are a very close Tom Baker impression.