Forget Julia's stint onstage during Swift's 1989 tour; if you've not seen Ellen's appearance you are in for a treat...
By way of a bit of background; you may recall that Swift's 1989 tour was a busy worldwide affair last year, and - to break up the show - Swift would invite her mates / famous faces up onstage. This is the first time Julia Roberts has seen herself gyrating onstage with Joan Baez and she looks mildly disturbed.
When DeGeneres points out that she hardly dressed up for the affair (compared to the amazing effort Ellen went to herself...), Roberts says: "In my defence, I had about 5 minutes notice. I was not dressed for 50,000 people", before launching into a very sweet story involving her sons' words of motivation.
