Doctor Who’s Tosin Cole has been cast in a big new US TV series – but does this mean he’s leaving the TARDIS?

Swept up into the “infamously corrupt Chicago criminal justice system,” Moses’ case is taken up by ageing public defender Franklin Roberts (played by American Crime Story’s Courtney B Vance), who sees this as his chance to finally challenge the institutional racism at the heart of the judicial system.

Created by The Night Of’s Peter Moffat and executive produced by Michael B Jordan, 61st Street is described as “a two-season television event” with eight episodes per series, and will apparently debut in 2021.

All of which raises a big question for Doctor Who fans – is Cole leaving the series? Frankly, given Doctor Who’s long shooting schedule it’s hard to see how he’d fit in filming for 61st Street at the same time, especially given the two-series commitment.

And rumours of Cole’s departure have been circulating for a while, especially after the actor signed up for a number of convention appearances without the other cast for after the current series ends. Meanwhile a new trailer for the series has noted his character Ryan’s dissatisfaction with TARDIS life, hinting that he could be looking for an exit...

“How long is this gonna last, Yaz?” he asks Mandip Gill’s fellow companion. “Is this our lives?”

But his departure isn’t certain. After all, it’s eminently possible that Cole has more time to shoot his new series in Doctor Who’s current filming break, and we should note that compared to Who, a drama like 61st Street (which doesn’t need new sets, characters and locations for every episode) wouldn’t necessarily take up as big a portion of the year.

Still, with all that said we can’t help but wonder if we’re looking at the last days of Ryan Sinclair, and whether that means Jodie Whittaker’s Doctor could be looking for some new help around the TARDIS sooner rather than later.

RadioTimes.com has contacted the BBC for comment.

Doctor Who airs on BBC One at 7:10pm on Sundays