The Falcon and the Winter Soldier adds major star to the MCU in villainous comic book role

Louis-Dreyfus has joined the cast as Contessa Valentina Allegra de la Fontaine, a long and confusing name that the character herself pokes fun at in a humorous debut – just don't call her Val.

Valentina is indeed a notable figure from the comic books and the casting of such an established star suggests she could be a major player moving forward, with a future appearance already rumoured for an upcoming Marvel movie.

Read on for everything you need to know.

The Falcon and the Winter Soldier: Julia Louis-Dreyfus cameo explained

The Falcon and the Winter Soldier writer Malcolm Spellman had previously told fans that a "grounded" new character would be making their first appearance in episode five, but no details had leaked on their exact identity.

Of course, now we know that it's none other than Julia Louis-Dreyfus who is strutting into the Marvel Cinematic Universe in high-heeled boots that she tells us are "not made for walking".

The multi-Emmy winner, best known for her roles in US comedies Seinfeld and Veep, strolled up to disgraced Captain America John Walker and his wife following a court hearing that saw him stripped of his military rank.

She introduced herself as Contessa Valentina Allegra de la Fontaine and made some intriguing comments that have left her motives unclear.

In reference to Walker's violent outburst against a member of the Flag Smashers, she said that she would have "killed the bastard too" and went on to assure him that taking the super soldier serum was the right thing to do.

She leaves the Walkers with her card and tells John to pick up the phone when she calls, but never clarifies exactly what it is she has planned for him.

Walker's wife remarks that the card has nothing on it, only adding to the air of mystery surrounding Valentina, but we can shed some light on what her intentions could be by examining the character's comic book history.

Who is Marvel's Contessa Valentina Allegra de la Fontaine?

Contessa Valentina Allegra de la Fontaine made her first comic book appearance all the way back in August 1967, debuting in espionage tales featuring super-spy Nick Fury.

She made a big impression on the SHIELD director by flooring him with a judo throw shortly after their introduction, later becoming a senior agent in the security organisation.

Valentina went on to have a romantic relationship with Fury and, as a result of this close bond, was demoted to a lower profile position in SHIELD when he went on the run after orchestrating an unlawful covert mission in Latveria.

While originally depicted as a heroic figure, Valentina has taken on a villainous role in recent stories, joining the terrorist organisation HYDRA and adopting its leadership title of Madame Hydra.

It was also revealed that Valentina is not Italian, as she had always claimed to be, but rather a Russian sleeper agent who had acted as a mole throughout her entire career with SHIELD.

Given this comic book history, it is possible that Louis-Dreyfus' incarnation of the character could be working to rebuild HYDRA after its devastating defeat in Captain America: The Winter Soldier.

Alternatively, some have speculated that she could be putting together the Thunderbolts, a team comprised of reformed super villains that have long been rumoured for the MCU.

Is Contessa Valentina Allegra de la Fontaine in Black Widow?

Following Valentina's appearance in The Falcon and the Winter Soldier, Vanity Fair published a report claiming that the character had originally been intended to make her debut in the solo Black Widow movie.

Due to the coronavirus pandemic playing havoc with Marvel's Phase Four release schedule, she has popped up here instead and it's currently unclear whether her Black Widow appearance will go ahead or be cut from the film.

However, with the comic book version of the character known to have Russian heritage, it's quite possible that she could play some role in the origin of Scarlett Johansson's former KGB spy.

If Valentina is assembling the Thunderbolts, it has been speculated that Natasha Romanoff's adoptive sister Yelena Belova (Florence Pugh) could be approached to join, in addition to John Walker (Wyatt Russell) and Baron Zemo (Daniel Brühl).

Black Widow is now scheduled for simultaneous release in cinemas and on Disney Plus in July, with no further delays expected, so we should have our much-needed answers fairly soon.

The Falcon and the Winter Soldier is available to stream on Disney Plus. Check out more of our Sci-Fi and Fantasy coverage or visit our TV Guide to see what's on tonight.