Los Angeles - Rita Ora reportedly cheated on Robert Kardashian with Jonah Hill.
The 22-year-old How We Do singer - who split from the Keeping Up With The Kardashians star earlier this month after which he publicly accused her on Twitter of being unfaithful to him - allegedly spent the night with the 29-year-old 21 Jump Street star while she was still dating the reality TV star.
A source told UsMagazine.com: "Rita spent the night with Jonah during a trip to New York."
The British singer reportedly met Jonah at a nightclub and went home together but Robert quickly found out.
'I'm actually disgusted'
In now deleted messages on his Twitter account, Rob angrily accused his ex-girlfriend, whom he dated on and off for more than a year, of cheating on him.
He posted: ''She (Rita) cheated on me with nearly 20 dudes while we were together, I wonder how many she will sleep with now that we apart?
"But I mean 20?!!! How can a woman who is so busy trying to start her own career have time to be with so many dudes all while in a relationship?! (sic)"
Rob, 25, added: "I'm actually disgusted a woman could give up her body to more than 20 dudes in less than a year's time while trying to start a career."
The pair's separation had been blamed on Rita's hectic work schedule and their incompatible jet-setting lifestyles.