Viewers hoping to watch The Last Kingdom season 4 are in for a long wait. Filming for the new season has not yet started despite the show's renewal in December on Netflix and it might be a while before the cast and crew are back together again on the set's location in Hungary.

Lead star Alexander Dreymon has just signed up for a new movie, Horizon Line, which will begin filming this February in Mauritius, Dublin, and London, according to Variety. The film will also star Get Out actress Allison Williams with Mikael Marcimain as director. 

Horizon Line is from a script by Josh Campbell and Matt Stuecken, who worked on 10 Cloverfield Lane. Dreymon and Williams will play ex-lovers who have been unexpectedly reunited for a friend's destination wedding. But their plane's pilot suffers a heart attack so their characters must find a way to safely get back to land. 

This new project is expected to keep Dreymon's schedule tied for the next three months, which essentially means that production of The Last Kingdom season 4 won't begin until his other commitments are through. But his other co-stars are also currently working on different TV projects on location thus the actual production for the news installment might likely start later this year.

According to Digital Spy, the premiere dates in between seasons for The Last Kingdom have always been erratic. The first season, which debuted in October 2015, did not get a follow-up until March 2017. The third season, on the other hand, debuted in November 2018 so season 4 might either get a spring 2020 or a late 2020 release.  

To be fair, however, fans did not anticipate the early renewal for The Last Kingdom season 4 last December. Netflix gave the show a green light just a month after the third season's episodes were made available on the streaming platform when it used to take longer to renew the show.

At any rate, curious viewers who have read Bernard Cornwell's Saxon Stories, the show's original material, are wondering how they'll make Dreymon's character, Uhtred of Bebbanburg, a lot older in "The Last Kingdom" season 4. The actor is currently 35 years old but his character, at this point in the story, should be in his mid-50s or early 60s.

The Last Kingdom is a historical dramatization of the lives of the British in the Medieval period. Aside from Dreymon, the series also stars Emily Coz (Brida), Ian Hart (Beocca) Toby Regbo (Aethelred) and Millie Brady (Princess Aethelflaed).