'Arrow': "Fundamentals" Trailer Puts Oliver Back in His Season 1 Costume

The CW has released the new teaser for next week's episode of Arrow, titled "Fundamentals," and it features Oliver in a return to his season 1 costume.

Grease paint and everything.

This is a curious thing for him to be wearing, since not long ago Stephen Amell tweeted that he had not yet appeared in a flashback scene in season six. At that point, he was at least 21 episodes into filming, which means that presumably the shots of Oliver in his season 1 costume in next week's eighteenth episode of the season will not be a flashback.

Of course, the flashback he was alluding to -- an appearance by Tommy Merlyn -- pretty closely fits the description of next week's episode provided by the network. You can read it here:

In his darkest place yet, Oliver (Stephen Amell) wonders if he has failed at everything – being a father, a mayor and a hero. His frustration rising, Oliver lashes out at Felicity (Emily Bett Rickards) and William (guest star Jack Moore). A surprising visit from an old friend has Oliver questioning his next move.

Tommy was a fan-favorite series regular in the show's first season before he died in the finale. The character has appeared in flashbacks a handful of times since, and most recently appeared in "Crisis on Earth-X," the four-show crossover event that brought together the casts of Arrow, The Flash, Supergirl, and DC's Legends of Tomorrow.

In the context of "Crisis on Earth-X," Donnell played the Earth-X doppelganger of Tommy, who dressed as the villain Prometheus and hailed from a planet where Nazis won the second World War.

Tommy is not the only relic of the show's earliest days to be making a comeback in the tail end of season 6: on last night's episode, it was revealed that Ricardo Diaz has taken over the Vertigo trade and is keen to reintroduce that designer drug, which appeared heavily in the show's first two seasons and less so in the years since, to the streets of Star City.

Tommy could, one guesses, be a Vertigo-inspired hallucination, although Amell's comments about a flashback seem to make that less likely.

Ben Bray directed the episode, which was written by Speed Weed & Emilio Ortega Aldrich.

Arrow airs on Thursday nights at 9 p.m. ET/PT on The CW. "Fundamentals" will premiere on Thursday, April 12.