So who's on next? Which actor will replace Matt Smith when he departs Doctor Who at the end of the year?
The question has sparked the kind of furious speculation that hasn't been seen since . . . oh, the furious speculation when Smith's predecessor, David Tennant, stepped down.
In all probability the new Doctor has been chosen already. After all, the regeneration scene will be the climax of this year's Christmas special; given the type of elaborate, special effects-heavy production Doctor Who has become, that's not the kind of programme you can knock together in a fortnight.
The people behind the series take confidentiality very seriously. On The Graham Norton Show last year, Jemma-Louise Coleman, who plays the Doctor's current companion, Clara, revealed how she'd had to keep the news that she'd landed the plum role a secret, even from her closest friends, for several weeks before the official announcement was made.
But cats have a habit of getting out of bags. The fact that Christopher Eccleston, the first actor to play the Doctor when the programme was taken out of mothballs in 2005, would be leaving after one series leaked out just four days after the first episode was broadcast.
Assuming some internet spoilsport hasn't blown the gaffe by the time you read this, the who's Who? guessing game will continue, and the favourite seems to change by the day.
Earlier in the week, several newspapers and entertainment websites were saying Rory Kinnear, son of the late comic actor Roy Kinnear, was a shoo-in for the part. Bookies gave him odds of 3-1.
Kinnear (35), an award-winning stage actor who's played some of the juiciest Shakespeare biggies, including Hamlet and Iago, has clocked up some impressive TV and film credits.
He received plaudits as Margaret Thatcher's husband Denis in the BBC4 drama The Long Walk to Finchley, and has played MI6 chief of staff Bill Tanner in the James Bond movies Quantum of Solace and Skyfall.
Most pertinently, he co-starred alongside Mark Gatiss – who has written numerous Doctor Who episodes – in the latter's BBC4 adaptation of HG Wells' sci-fi adventure The First Men in the Moon, so that might give him the extra edge.
By midweek, however, the smart money had supposedly shifted to Ben Daniels, from Law & Order UK and Netflix's House of Cards. Like Kinnear, Daniels has a strong stage pedigree; if cast, he'd also be the first openly gay actor to play the Time Lord.
As always, there have been calls for a black actor to be cast, which would certainly be a welcome and refreshing change. There's no shortage of impressive candidates, either, with names like Idris Elba, Adrian Lester, Chewitel Ejiofor, Paterson Joseph (briefly a favourite when Tennant stepped down), David Harewood (late of Homeland) and Ashley Walters, who was excellent in Channel 4's Top Boy last year, being bandied about.
But many of these are already established names with thriving careers elsewhere – including, in Elba and Harewood's cases, Hollywood – and whether they'd want to give all that up for Doctor Who is debatable.
The idea of the Doctor being reincarnated as a woman (Olivia Colman, Helen Mirren and, ridiculously, Miranda Hart were touted) is hopefully a non-starter. The fact that the character is male has always been central to the programme's dynamic. The only justification for a sex-change would be the novelty factor, and that's no justification at all.
The funny thing about all this is that many of the names being mentioned now (Russell Tovey, for example, who the bookies have as a 10-1 shot) are the same ones that cropped up when Tennant quit. And we all know how that turned out.
If I were a betting man – which I'm not, because I usually lose – I'd stick a few bob on Kinnear; he's a terrific actor and still a fresh face to viewers.
As Matt Smith, a virtual unknown when he took over, proved during his three-year tenure, unfamiliarity can often breed content.