Frozen 2: Five questions from the trailer we just can't let go

Elsa (Idina Menzel), Anna (Kristen Bell) and Kristoff (Jonathan Groff) in the Frozen 2 trailer

The first trailer for Disney's Frozen 2 has arrived.

The film, which will be released in November, is a sequel to 2013's Frozen, which became the highest-grossing animated movie of all time.

The original told the story of sisters Anna and Elsa and was loosely based on Hans Christian Anderson's The Snow Queen.

Disney aren't giving much away about the plot in the trailer, which clocks in at just under two minutes long.

Disney announced they would be making a sequel in 2015 and work began on it in September 2017.

The first trailer appeared online on Wednesday.

It's left us with a lot of burning questions.

1. What's with the dark new tone?

The cold never bothered them anyway

It's a beautiful autumn in the kingdom of Arendelle, but ominous music signals that all is not well.

Kristen Bell's Anna tries to cross dangerous looking rocks, and her sister Elsa (Idina Menzel) uses her icy powers to try to cross a stormy sea.

Later, Elsa and magical snowman Olaf (Josh Gad) are surrounded by flames. Anna's fiance Kristoff (Jonathan Groff) races through the forest on his reindeer Sven, flanked by other reindeer.

In the final shot, Anna grabs Kristoff's sword and lunges at the audience.

Who or what is threatening the kingdom? The trailer doesn't show us, but the internet is excited anyway.

2. Is climate change causing trouble in Arendelle?

The trailer opens with a 40 second sequence of Elsa trying to cross a raging sea.

All those wild waves have spawned some an even wilder theory amongst some Frozen fans that the sequel is actually about... climate change!

3. Could one of these new characters be Elsa's girlfriend?

Two new characters were fleetingly revealed in the trailer, prompting a lot of speculation about their identities.

They are a woman with red hair, and a blond figure who emerges, floating from a pile of leaves. One of these characters may be voiced by Westworld actress Evan Rachel Wood, who is attached to the film in an unknown role.

Perhaps these new characters could be the villains of the piece, but some fans are hoping otherwise.

Frozen's writer and co-director Jennifer Lee has reportedly been considering giving Elsa a female love interest.

Elsa's sexuality was not made clear in the first film, but many fans signed a petition calling for her to come out as gay.

Lee has previously said there have been "tons of conversations" about whether Elsa will become the first Disney princess to have a girlfriend.

So perhaps one of these characters could be a love interest for our heroine?

• Frozen 2: Will Elsa get a girlfriend in new movie?

• Disney's Frozen and the 'gay agenda'

4. What's the significance of the floating diamonds?

Strange floating diamonds are seen hovering outside the castle, as Anna watches, in a short section of the trailer, prompting speculation.

Sharp-eyed fans have also noticed that the newly-released poster for the film features connecting diamonds which all contain different patterns.

Can we assume the diamonds are going to play a major part in the film? It certainly looks that way.

5. Why have Anna and Elsa changed their looks?

Elsa pictured wondering how much merch she can sell

Actually, this one is probably easy to guess. Dolls based on the Frozen sisters have been flying off the shelves since the original film's release.

Anna and Elsa both sported new outfits in the previous Frozen short animations released after the original film, Frozen Fever and Olaf's Frozen Adventure, and merchandise featured the new outfits.

With that in mind, perhaps it's no surprise that Elsa is sporting a new icy blue ensemble and Anna has ditched her trademark braids for a new half-up, half-down hairdo.

We'll have to wait until the film is released in November to find out if Frozen 2 will be as successful as its predecessor.