52nd Annual GRAMMY Awards - Salute To Icons Honoring Doug Morris - Roaming
Swift and Perry were still friendly in 2010
Katy Perry appears to have accused Taylor Swift of "capitalizing on the take down of a woman" after the singer got into a spat with Nicki Minaj.
Earlier this week Minaj complained about her single Anaconda being snubbed in the video of the year category at this year's MTV Video Music Awards.
In a series of tweets she suggested that the music industry was biased against African-American women and preferred female singers with "very slim bodies".
"If your video celebrates women with very slim bodies, you will be nominated for vid of the year," she wrote.

Marc Jacobs - Backstage - Mercedes-Benz Fashion Week Fall 2015
Minaj believes there is a bias towards white artists
Swift, who received the most nominations for the awards, responded by inviting Minaj to join her on stage if she wins.
"I've done nothing but love and support you. It's unlike you to pit women against each other. Maybe one of the men took your slot," tweeted Swift, who has cast herself as a feminist.