Marvel's 'What If...?': Who Is in the Voice Cast for Episode 1?

Marvel's What If...? will air weekly from August 11 on Disney+, and the first episode focuses on Hayley Atwell's character Agent Peggy Carter.

What If...? is set in the Marvel Cinematic Universe's (MCU) multiverse, and examines how certain key events in the MCU may have happened differently.

The animated series' first episode asks the question: what would have happened if it was Agent Carter who took the Super Soldier Serum instead of Steve Rogers during World War II?

The series' trailer, which was released on July 29, showed the spy take on the title of Captain Carter.

According to IMDb, many of the original cast from 2011 film Captain America: The First Avenger return to reprise their roles in animated form, and Newsweek can reveal who will be back.

Who stars in the first episode of Marvel's What If...?

Hayley Atwell returns to voice Peggy Carter, and gushed in a social media post on Monday about seeing her character in a "position of visibility and power."

Sharing a picture of her character in costume as Captain Carter, she wrote: "Here she is... Our Peg in a greater position of visibility and power; raising the standards for female representation in this genre...

"I love my Marvel family and their expansive vision... See Peggy Carter and Steve Rogers in a whole new way this Wednesday when the first episode of Marvel Studios' @WhatIf starts streaming on @DisneyPlus."

Dominic Cooper will also be back to reprise his role as Howard Stark, father to Iron Man Tony, while Sebastian Stan is voicing his character Bucky Barnes, aka Winter Soldier.

What If promotional poster
Agent Peggy Carter as Captain Carter in the promotional poster for "What If...?" Episode 1 Disney+

Cooper teased what was to come for his character by sharing a picture of himself in character on Instagram, and telling fans: "Howard Stark 10 years ago contemplating @whatif he could invent a machine that allows him to be someone else."

Another actor to return is Stanley Tucci, who will be voicing his character Dr. Abraham Erskine—the scientist who created the Super Solider Serum.

Toby Jones also returns as villain Arnim Zola, the scientist working for HYDRA who took Barnes, experimented on him and made him into a HYDRA operative in the Winter Soldier program.

Samuel L. Jackson portrays Nick Fury once again, though it is unclear how much of a role he will play in the episode given his character only met Captain America in the MCU after he had been frozen in ice for 70 years.

Neal McDonough will also return as Dum Dum Dugan, a soldier in the United States Army who fought alongside Rogers and Barnes in World War II.

Jeffrey Wright stars as The Watcher, the new character is the narrator for the whole series and will appear in every episode.

Marvel have yet to reveal who will voice Steve Rogers in the animated series, so it is unclear if Chris Evans will be joining the voice cast.

What If...? begins streaming on Disney+ from August 11, with episodes being made available weekly on the VOD platform.