Katy and Rob have been close for a while
The singer and Robert, 26, are close pals and the Twilight hunk supported Katy through her recent split from John Mayer.
She’s said to have made the awkward confession to Kristen, 23, at a karaoke night.
‘Kristen looked like she wanted to run away,’ claims an insider.
It seems Katy, 28, won’t be getting her hands on Robert anytime soon – Kristen is said to finally have won back his trust after cheating with married director Rupert Sanders last year.
The couple have been snapped together on numerous occasions over the past few weeks and Robert celebrated Kristen‘s birthday with her on Tuesday.
SEE PICTURES Katy Perry at Nickelodeon Kids’ Choice Awards 2013