Katy Perry has reportedly had a massive falling out with pal Rihanna, after she failed to attend her wedding with Russell Brand.

After RiRi revealed that she missed Katy's big day because of promotional duties for her new album Loud, allegations have now suggested that they are 'barely talking.'

According to Now magazine, a 'close friend' of the Only Girl (In The World) singer has claimed that Rihanna didn't want to be maid of honour, because she doesn't think Russell is good enough for Katy.

The insider told the publication: "Rihanna told Katy she didn't think she should go through with it. She said she couldn't be a part of Katy's wedding since she absolutely doesn't approve."

They continued: "Rihanna and Russell are very rarely photographed together because she doesn't think he's good enough for Katy. She just doesn't get the attraction."

The pal also confessed that during Katy's hen-do in Las Vegas, the 22-year old Barbadian beauty spent most of the evening trying to talk Perry out of marrying Russell.