But one that no doubt came as a surprise to viewers was the hint to Clint Barton’s (Jeremy Renner) wife Laura’s (Linda Cardellini) past as a S.H.I.E.L.D agent.

The connection to Laura and her past life was revealed in the show’s final moments with a simple item: a watch.

Here is everything you need to know about what that item means, and which classic Marvel Comics hero it makes Laura.

Is Clint Barton’s Wife Laura Agent 19?

When Clint arrives home for Christmas after fighting off Fisk’s men of the Tracksuit Gang with Kate Bishop (Hailee Steinfeld), he hands his wife a watch that was once hers and had been put up for auction on the black market.

Laura turns the Rolex over, and the back is revealed to have a carving with the S.H.I.E.L.D symbol on the back and the number 19, clearly pointing to her being Agent 19.

In the Marvel Comics, Agent 19 was a member of S.H.I.E.L.D who had a PhD in biology and also used the moniker Mockingbird when in the field.

The character was known as Barbara “Bobbi” Morse in her everyday life, and an iteration of her actually appeared in the TV show Agents of S.H.I.E.L.D, and she was portrayed by Adrianne Palicki.

Despite this link within the Marvel Cinematic Universe (MCU), it seems Laura is actually Agent 19 given the number on the back of the watch.

Barbara was designated the number 19 by S.H.I.E.L.D in the Astonishing Tales comic series in the 1970s.

The character then met Hawkeye in a mini comic series that focused on the archer in 1983, in a storyline that saw Mockingbird investigate the company where Clint worked as the chief of security.

While they initially started out as adversaries, the comic by Mark Gruenwald ended with Mockingbird and Hawkeye becoming romantically involved, and they were so enamored with each other that they eloped.

In the same year, writer Roger Stern’s Avengers run introduced the pair as a married couple and they set up the Avengers West Coast in Los Angeles, a second team of Earth’s mightiest heroes.

Mockingbird was killed in the Avengers West Coast comics in 1993, and a Skrull later pretended to be her in the Secret Invasion comics that were published between 2008 and 2009.

By the end of the Secret Invasion comics it was revealed that Mockingbird was alive and had been abducted by the Skrulls, and after being saved by Iron Man she was reunited with her husband.

Given Mockingbird is Barbara in the comics, and not Laura, it is clear her storyline will have diverged significantly from the original source.

And even though Marvel intends to make a Secret Invasion Disney+ series it is unlikely to take the same storyline as the comic, namely because Iron Man died at the end of Avengers: Endgame.

The reveal that Laura is Agent 19 is most likely just a reference to Mockingbird’s part in Clint’s life in the comics, and it certainly serves as an explanation as to how Clint met Laura in the first place.

While it points to her time at S.H.I.E.L.D it doesn’t seem likely Laura will become a predominant part of the Avengers team anytime soon.

Hawkeye is available to stream in full on Disney+ now.