The star's set on the closing night of the festival was thrown into jeopardy following her recent hospitalisation with a mystery illness, but on Saturday (04July15), Jessie J announced she was out of hospital and "feeling much better".

In a post on, she writes, "I'm out of hospital... Still very fragile but much better. I will be at Wireless... Not my usual crazy running around self, but I will be there. Can't wait."

The singer, who underwent two rounds of surgery last month (Jun15), is also due to perform at T In The Park festival in Scotland later this month (Jul15).