International superstar Rihanna has been announced as the second headline act to play at the UK’s biggest festival this summer on Hackney Marshes, which is set to rival Glastonbury.

She will take to the stage on the final night of Radio 1’s Hackney Weekend - Sunday June 24 - while hip-hop heavyweight Jay-Z tops the bill on Saturday.

Now all those registered are being urged not to forget to apply for tickets tomorrow and Monday.

The American duo join Brit sensations Tinie Tempah, Jessie J and Ed Sheeran.

The radio station is giving away 100,000 tickets to listeners, and the event will feature 100 acts performing on six stages.

Other acts on the roster are Florence and the Machine, Professor Green, Leona Lewis, DJ Fresh, Plan B, Flo Rida.

A massive 50,000 tickets have been reserved for Hackney residents, but it is unclear whether supply has exceeded demand, as last Thursday just 15,000 people from the borough had registered before registrations closed Monday.

Event director Jason Carter said tickets began moving much quicker towards the end, after registration in Hackney had been slow.

“Just a couple of thousand had registered at the beginning, which was a shame as we had a huge number we were holding back and if those tickets aren’t used we will tip them into the pot for the rest of the country,” he said.

“Part of the problem is that people don’t think they have a chance, when in fact they do. What worries me is when it’s June and its two weeks away, with the big vibe Jay Z is coming, they’ll wake upand it’ll be, ‘Too late, mate, it was back in March’.”

Registration required a photo to stop tickets being sold on. It’s believed this may have put some people off.

Festival lovers as far away as Canada have taken to social networking site Twitter to ask how to obtain a coveted ticket.

Those registered must now get online at 11am on Sunday and 4pm on Monday to secure tickets.

There will be 50,000 available to book on each day - 25,000 for Saturday and 25,000 for Sunday - and allocation will be on a first-come, first-served basis, once where you live is taken into account.

The quickest way to apply is at bbc.co.uk/radio1.

Those unable to access the internet can call 0844 873 7347. Tickets are free but there is a handling fee of �2.50.

BBC3 will screen the event for anyone who wasn’t lucky enough to bag a golden ticket so they can see how much fun they’re missing.