What do Pop Superstars tweet each other about? Their similar billboards of course. Pink and Katy Perry who are both spokeswomen for Cover Girl shared cute tweets the weekend before they are both up for Grammy Awards.



Both artists are scheduled to sing at the Grammys this Sunday night; Pink will duet on "Just Give Me a Reason" with fun. frontman Nate Ruess, while Katy will perform an as-yet-unannounced track. Bothare nominees as well.