New music. A LOT of new music: When her iTunes performance was announced, Lady Gaga promised she would play an hour of all-new music. The show will be fans' first opportunity to hear tracks from her upcoming third studio album, ARTPOP - if not every single one...
And some hits - surely?: But hang on, surely she won't leave Camden Roundhouse without cracking out 'Bad Romance' or 'Edge Of Glory'? That would be criminal. We'd put money on an over-running show, with hits saved for a lengthy encore after playing through ARTPOP in full.
A meet and greet: Lady Gaga is unquestionably brilliant with her fans. She may have been accused of exploiting their devotion when urging them to download her 'Applause' single numerous times, but the star is continually seen meeting her Little Monsters as she travels around the world. A brief 'hello' to fans in the queue should be expected - so get your cameras at the ready.
Drum solos: Lady Gaga - singer, attention seeker, face-painter... and batshit crazy drummer? In a video teaser for the iTunes gig, Gaga is seen hammering seven shades of hell out a drum kit as she rehearses new track 'Swine'. Despite her previous albums having had a heavy electronic and dance feel, will ARTPOP be a more live experience? We'll know all on Sunday.
A special guest (it's probably Elton John): Lady Gaga has promised she will perform with a special guest at her London gig, and despite initial speculation that it might be Beyonce (she has confirmed there is a sequel to their duet 'Telephone' on her new album), fans are certain it will be Elton John instead. Who's not a bad second choice at all!
Sea-shell bras: Lady Gaga's iTunes gig will have an 'under the sea' theme, and the star has promised seashells, seahorses and starfish - for the event she has oddly dubbed 'Swinefest'. Azealia Banks is none-too-pleased however, having staged her own Mermaid's Ball shows in 2012 and accused Gaga of being 'late' on Twitter.
Hysteria. Manic hysteria: One Direction fans aside, no fanbase can quite compare to Gaga's Little Monsters. Her devoted fans will go to any length for their icon and are happy to toss death threats around Twitter at the drop of the hat (not encouraged by Gaga, FYI). Expect not only the Roundhouse, but all of Camden to shake with the sound of screaming on Sunday night.
No Perez Hilton: Lady Gaga and Perez Hilton have long been firm friends - until he criticised her 'Applause' single online. The star later accused the celebirty blogger of stalking her, suggesting she was under threat of being shot in the head when he was spotted by a fan at her apartment building. She wasn't, he was just looking for a new flat. Nonetheless, he won't be making a trip to the UK for the show - guaranteed.
Nudity: Basically, it will be an absolute miracle if Lady Gaga doesn't get naked at some point during her show. She bloody loves getting her kit off and does so at every available opportunity