That is what Gaga tweeted the day after Katy's tour began.

Now, this video from Katy's tour has surfaced where it looks like Katy is spitting green slime. Seems likes a similar concept from Lady Gaga's SXSW controversial performance where she was vomiting on stage (I will spare you from having to watch that video = gross).

Look, I love both of these artists, but should Gaga really be calling anyone out? Gaga meet Madonna. Why do we have to fight... can't we all just get along?