A pretty major Black Widow spoiler may have just been accidentally unveiled thanks to a recent interview with star Rachel Weisz. Potential SPOILERS to follow, obviously. While appearing on Jimmy Kimmel Live, the host may have let too much slip when introducing the actress saying, "Our first guest tonight is an Oscar winner who is about to leap into the Marvel Cinematic Universe. She plays Melina Vostokoff in Black Widow." When Weisz stepped out, she was quick to point out Kimmel's mistake, even claiming that her character's last name is one of Marvel Studios' closely guarded secrets. Oops.

"I think we are prohibited from saying Melina's second name," Rachel Weisz said. "I think it's a Marvel Cinematic Universe secret...But, oh well, you've done it now."

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The reason why this is such a secret it that Weisz's character having the last name "Vostokoff" suggests that things are not as cosy as they seem between her and Scarlett Johansson's Natasha Romanoff. In the comics, Melina Vostokoff is known as the Iron Maiden, a Russian government agent who harbours a deep-seated hatred for Black Widow after living in her shadow for so long. Eventually, she leaves the service of Russia and becomes a freelance assassin and mercenary, even joining a group of assassins tasked with assassinating the Black Widow.

So, while the trailers so far have shown Melina and Natasha to be part of a loving, if unconventional, little assassin family, it could well be that Weisz is looking to settle a score with Black Widow. Interestingly, the identity of the movie's villain, Taskmaster, remains a secret, with many having theorized that it could be Rachel Weisz under the skeleton mask. Is it possible that Marvel have merged the characters of Melina Vostokoff and Taskmaster in hopes of a shocking reveal? Yes, yes it is. Very possible, in fact.

As well as the accidental reveal, Weisz did offer some Marvel approved details about her character including that she is "highly-skilled, highly-trained in combat, [and] fluent in 25 languages." The actress also offered some insight into some of the footage that has been shown saying, "She runs kind of, well, a pig farm. That's where the family have met me [in the clip], at my scientific lab where I also keep pigs which I experiment on."

Black Widow finds Natasha Romanoff confronting the darker parts of her famous ledger when a dangerous conspiracy with ties to her past arises. Pursued by a force that will stop at nothing to bring her down, Natasha must deal with her history as a spy and the broken relationships left in her wake long before she became an Avenger. Black Widow will provide some insight into the origins of one of the founding Avengers, even revealing details regarding the famous mission in Budapest.

Black Widow will be the first installment in Phase Four of the Marvel Cinematic Universe and is directed by Cate Shortland and produced by Kevin Feige. Scarlett Johansson reprises her role as Natasha Romanoff AKA Black Widow (possibly for the final time) alongside Florence Pugh, David Harbour, O-T Fagbenle, William Hurt, Ray Winstone, and Rachel Weisz. After being delayed several times amid the current circumstances, Black Widow is now scheduled to be released in the United States on July 9, 2021, simultaneously in theaters and through Disney+ with Premier Access.