Russell Brand has managed to resist having a proper dig at his ex-wife Katy Perry since their separation.But hours after their divorce was finalised over the weekend the funnyman let his guard down.Russell said: "Anyway, enough of you, I’ve had enough ar*e-ache from people called Katy in the last year.”Cue gasps from the audience and a naughty schoolboy grin from Russell.Someone who saw the recording revealed: "Russell was in great form, having some banter with the audience. Then he came across this audience member who was named Katy."They were having some chat about whether Katy could satisfy her boyfriend in bed when, all of a sudden, Russell shouted the comment about ar*e-ache."It was a blatant reference to Katy Perry."The look on his face as he laughed after saying the comment said it all.”It didn’t take long for Russell to get back to familiar material. He later Skyped two porn stars, who were in Miami, to talk about the morals of adult movies.Katy has made a couple of swipes while promoting her new movie, including when she was asked if Russell’s absence from her California Dreams tour was the reason for their split.She said: "Yes, if I could edit it any other way I would but that is exactly what it was. "I always had plans to make this record and usually with a record, you tour. "Touring is always important to me. It’s like a big IOU to my fans, because I know they are the reason I exist.”Now Russell has upped the ante it will be interesting to see if Katy hits back.