The meaning of something said by Groot in Avengers: Infinity War has been revealed and it's leaving fans in tears.
MAJOR SPOILERS FOR AVENGERS: INFINITY WAR FOLLOW
The revelation came via Guardians of the Galaxy director James Gunn on Twitter, in response to a fan's question.
Groot is famously only able to utter one sentence, "I am Groot"; but how he says it gives the sentence an array of different meanings.
At the tragic end of Infinity War, Groot is one of the many victims of the universe-wide massacre carried out by Thanos.
As the talking tree alien - voiced by Vin Diesel - dies, he emotionally reveals Rocket Racoon is his father.
After revealing what Groot's final line meant, Gunn says he wasn't prepared for just how upset it would make fans.
"I knew my answer to the spoiler question last night was touching and sad, but I really did not expect to wake up to so many tweets of people telling me they're crying," Gunn said in a follow-up tweet.
"Sorry for that if you're at work or whatever. But it means a lot to me you love the characters as much as I do."
Avengers: Infinity War is currently in cinemas and breaking several box office records, including being the fastest movie ever to pull in US$1 billion.