At what Con did Jensen Ackles describe how he did not want to film the end scene in "About a Boy" in which Dean seems to like the Taylor Swift song "shake it off".

I recall seeing Jensen Ackles talk about how he did not want to film the last scene of "About a Boy" in which Dean kinda smiles and leaves the Taylor Swift tune on the radio and then drives off in the Impala. He said they had to do a few takes because he intentionally acted the part as if Dean did not like the song and then was told just to do it. Did anyone else see/ hear him talk about this at a convention and if so what one?