Kristen Stewart wants to know exactly what's going on
And we can reveal that furious K-Stew, 23, confronted Katy, 28, in a phone call two weeks before the couple’s split became official.
Now‘s learnt K-Stew was angry that her friend had become close to Rob, 27, and called her demanding to know what was going on – just hours before she was due to see her at New York‘s Met Ball on 6 May.
‘Kristen called Katy to ask her straight out,’ says our source.
‘Katy was stunned and things got awkward.
‘She said there was no way she was messing with Rob, but Kristen didn’t believe her.
‘Katy got off the phone as soon as she could.’
Last Sunday, two weeks later, R-Pattz moved his stuff out of the £3 million gaff he shared with on/off girlfriend of four years Kristen in Los Feliz, LA, taking their dogs Bear and Bernie.
Reports claim he’d discovered she was back in touch with director Rupert Sanders, 42, with whom she was caught cheating last July.
However, our sources say it was her jealousy over Rob‘s friendship with Katy that played a bigger part.
Onlookers reported K-Stew getting upset with Rob as they dined in New York on 7 May, the night after her call to Katy, as he was texting someone else all evening.
‘Kristen went nuts then burst into tears,’ says a source.
The A-list trio had previously hung out together happily at Coachella festival in March.
Earlier this month Rob and Katy – who’ve known each other for years – were spotted at a gig at the Bowery Ballroom in New York, fuelling rumours that their close friendship was back on.
Friends insist Rob just values Katy‘s friendship during the rough patch, saying: ‘He and Kristen were arguing and Rob found comfort in Katy.
‘She’s fun to be with, not moody like Kristen.’
Read the full story about Kristen Stewart and Katy Perry in this week’s Now magazine dated 3 June 2013 – out now!
SEE PICTURES Robert Pattinson and Kristen Stewart – a love story in photos