Disney head honcho Alan Horn's recent confirmation to The Hollywood Reporter that filming had begun on Star Wars: Episode VII came as something of a surprise. Even by the tight-lipped standards of this notoriously secretive production, getting filming underway without anyone noticing was quite an achievement.

Nevertheless, despite all efforts to keep details a mystery since Disney announced its desire to resurrect the franchise following its $4bn purchase of Lucasfilm last year, some titbits have managed to creep through. Here are a few things we know, alongside a healthy smattering of rumour, hearsay and tittle-tattle.

The release date

18 December 2015

The budget

A pricey $200m, though this has to go down as one of the safest investments in human history.

The plot

Past perfect? ... Return of the Jedi. Photograph: Cine Text/Allstar/Sportsphoto Ltd

Horn said Episode VII would take place 35 years after The Return of the Jedi, using an original plot outline by George Lucas (who is involved as a creative consultant) as a template. The original script was said to be primarily concerned with the offspring of Luke and of Han and Leia, but that focus has now shifted to the creaky lead actors from the original trilogy, though the Solo and Skywalker nippers will still feature heavily.

The story of Luke, Han and Leia continued, of course, in the books, games and comics of the Extended Universe (most notably in Timothy Zahn's excellent Thrawn Trilogy), but it's been reported that the upcoming film will plough its own furrow instead of adhering to a pre-existing narrative. And, as far as confirmed plot details go, that's... about it.

The director

Star man ... JJ Abrams. Photograph: Marianna Massey/Marianna Massey/Getty Images

JJ Abrams. A decidedly safe pair of hands – one who's demonstrated a flair for bombastic populist sci-fi with his resuscitation of the ailing Star Trek franchise. Arguably more intriguing is his work on Super 8, whose Spielbergian sense of wonder and adventure would serve a Star Wars film extremely well. While something of an obvious choice, few would argue Abrams was a poor one.

The writers

The current draft of the script has been penned by Abrams alongside Lawrence Kasdan, co-writer of The Empire Strikes Back, Return of the Jedi and Raiders of the Lost Ark, from an original by Toy Story 3 writer Michael Arndt. The respective writers' CVs are definitely encouraging. A cheeky bonus also comes in the form of Damon Lindelof's absence. Sorry Damon.

The music

Fans of the series' rousing orchestral space operatics can rest easy: John Williams will once again provide the score.

The cast

Evil empire ... Adam Driver will play Episode VII's villain. Photograph: Larry Busacca/Getty Images

Though no official announcement has been made, Carrie Fisher has essentially confirmed the involvement of the original cast of her, Harrison Ford and Mark Hamill to the surprise of no-one at all but the delight of many. In February, Girls star Adam Driver was also revealed to be playing the film's main villain.

Casting rumours

Horn stated that most of the actors are in place, though, in this regard, "we're just not completely done yet". Rumours abound though in some cases salt should be pinched, particularly where anonymous "sources" are involved. Gary Oldman cagily confirmed that he's been approached to appear – both he and Benedict Cumberbatch were apparently mooted for the same role, with the script reportedly being tweaked to allow the involvement of both. 12 Years a Slave's Lupita Nyong'o has also met with Abrams to discuss a part, as have the ubiquitous Michael Fassbender and the reliably sinister Hugo Weaving, who's unsurprisingly been linked with the role of an Imperial Officer. Attack the Block's John Boyega, Breaking Bad's Jesse Plemons, Matthew James Thomas, Ed Speleers and Ray Fisher are rumoured to be in the running for the young leads.

Back for more ... R2D2. Photograph: Alamy

As for returning cast members, R2-D2 will appear, though it's unconfirmed whether Kenny Baker will return to play him. Peter Mayhew has been tenuously rumoured to reprise his role as Chewie, though his double knee replacement may prevent him from doing so, while Billy Dee Williams (Lando Calrissian) and Anthony Daniels (C-3PO) have both expressed interest in returning. Those elusive "sources" also suggest Ewan McGregor and Ian McDiarmid will return as Obi Wan Kenobi and Emperor Palpatine respectively, albeit in ectoplasmic form.

Will Episode VII be better than all the films in the prequel trilogy?

Yes.

With filming now underway at Pinewood you can expect the trickle of details to soon become a flood, but what little we know at this point gives us reason to be tentatively optimistic. What would you like to see in Episode VII? Let us know in the comments.

• This article was corrected on 7 April, to change the year of release from 2014 to 2015