After Natasha Lyonne's Byrdie was introduced in What If...?, one theory hints that she could be a major mystery character in 2025's The Fantastic Four: First Steps.
Natasha Lyonne plays a character named Byrdie, made specifically for the MCU and introduced as part of What If...? Season 3's massive cast. The character was seen alongside Captain Carter and Kahhori, hinting at her being a key figure in the show's final season.
Lyonne is also lined up for an undisclosed role in 2025's The Fantastic Four: First Steps next to Pedro Pascal, Vanessa Kirby, Joseph Quinn, and Ebon Moss-Bachrach. While actors playing multiple roles in the MCU is not uncommon, one theory behind Lyonne's place in the franchise is raising eyebrows.
Is Byrdie Secretly in Marvel Studios' Fantastic Four Movie?
Season 3, Episode 7 of What If...? introduced fans to the grown-up version of Natasha Lyonne's Byrdie, the offspring of Darcy Lewis and Howard the Duck. This mostly human character can sprout wings from her arms, allowing her to fly, and she also has cosmic energy manipulation powers.
However, what has Marvel fans' hairs standing up on end is that Lyonne was previously announced for a role in 2025's The Fantastic Four: First Steps in May 2024. Curiously, Marvel did not announce which character she played, nor have they confirmed her role since then.
Early theories pointed to her playing the MCU's take on Alicia Masters, who Emmy-winner Kerry Washington previously portrayed in Tim Story's Fantastic Four films from 2005 and 2007. However, many now believe Lyonne will again play Byrdie the Duck from animation into live-action.
Noteworthy is that Lyonne and her character, Byrdie, look quite similar, mainly sharing the same natural red hair color. Additionally, reports indicated that What If...?'s ending will significantly impact the MCU's live-action future.
Speaking with Phase Hero's Brandon Davis, Marvel Studios' Head of Animation, Brad Winderbaum, hinted that by the end of What If...? and throughout the rest of the Multiverse Saga, fans will see "how it all balances out:"
"By the time you get to the end of the season and the next couple years as the Multiverse Saga reaches its exciting conclusion, you will see how it all balances out."
How Could Byrdie Be Used in Fantastic Four?
One of the most important aspects of The Fantastic Four to remember is that it takes place in an undisclosed alternate universe apart from the Earth-616 timeline. It is set in a retro-futuristic, 1960s-inspired universe where the Fantastic Four are already well-regarded as celebrities and heroes.
Many theorize that this movie will end with the universe dying, whether from an Incursion or some other cosmic event possibly involving Galactus. This would undoubtedly mean the team must be brought to Earth-616, where Natasha Lyonne's Byrdie could play a role.
While her being a hero already in this universe is up for debate, with her insane power levels, she could be the one to save the Fantastic Four from their dying world. After all, now that an uber-powerful offspring of Howard the Duck and Darcy Lewis exists in the Multiverse, who's to say she can only exist in one timeline?
It would not be the first time a What If...? character has been used in live-action, as seen by Hayley Atwell's screen time as Captain Carter in Doctor Strange in the Multiverse of Madness. On top of that, the MCU is also familiar with highlighting original characters not seen in the comics (see Phil Coulson).
Given how similar Byrdie and Lyonne look, this series could be the natural way to introduce an impactful character before she takes on a bigger role in the movies.
When Will Fans Learn More About Natasha Lyonne in The Fantastic Four?
Natasha Lyonne has not been shown in privately released concept trailers or early concept art pieces highlighting the film's four leads for Marvel Studios' The Fantastic Four.
Lyonne still has the end of What If...? to introduce fans to Byrdie further. However, with 2025 fast approaching, her spot in The Fantastic Four's cast list will surely gain attention quickly.
Many expect The Fantastic Four's first trailer to be released sometime soon. This could happen alongside Captain America: Brave New World (debuting February 14, 2025) or as one of Marvel's trailers released at Super Bowl LIX on February 9, 2025, less than one week earlier.
It is safe to say that Lyonne's future with Marvel Studios is growing brighter after introducing such a monumental character on the animated side.
All eight episodes of Marvel Studios' What If...? are now streaming on Disney+. Natasha Lyonne will be seen again in Marvel Studios' The Fantastic Four: First Steps, which flies into theaters on July 25, 2025.
