The 'I Need Your Love' hitmaker was partying with friends, including the Icelandic singer, DJ Diplo and her ex-boyfriend Skrillex, on the tropical island when they were wrongly thrown out after being mistaken for gatecrashers, but the fun didn't stop and they just moved the party to the reception area.
Ellie told the new issue of Q magazine: ''I think it was in Costa Rica. A few of us were thrown out but then they realised they'd made a mistake. I can't quite remember actually because I was quite drunk. Obviously. There was me, Bjork, Diplo, Skrillex and loads of people starting our own party in the reception area. I'm afraid I can't remember all the details.''
The singer/songwriter also revealed she can have quite a bad temper when people upset her.
Despite her usually quiet demeanour, Ellie, 26, insists she doesn't take any crap off people and was tempted to punch a man at a bar in Camden, north London, recently.
She added: ''I've never been in a fight, but last week in a bar in Camden some guy was dared to come up and give me and my friends the middle finger. I wanted to punch him in the face, but I didn't.''
Take a look back at October's inaugural event.
The film is expected to continue without Mendes' involvement.