Will Poulter had a heartbreaking reason for dressing up as Sid from Toy Story for Halloween

Will Poulter once dressed up as Sid from Toy Story for Halloween - but his reason for doing so was very moving.

Poulter was going 'undercover' on social media for a feature of GQ as part of his press tour for Guardians of the Galaxy Vol 3.

Whilst on Twitter, the actor came across a tweet from a user asking why Poulter had dressed up as Sid Phillips, the boy with a penchant for destroying his action figures in Toy Story.

The user tweeted a picture of Poulter, dressed in Sid's famous black skull shirt and holding a magnifying glass and a Woody doll, and asked: "Thought he [Poulter] hated this comparison, so how did this happen in the end? Knowing him he must have done it for a reason."

The We're The Millers star then got pretty candid about his decision to don the skull T-shirt for Halloween in 2017.

Twitter/@PoulterWill

In response, the 30-year-old actor said: "I did do it in light of some of the comparisons between me and Sid from Toy Story that were going around on the internet.

"I work with Anti-Bullying Pro and the Diana Award, I did it during anti-bullying week to raise awareness of that organisation.

"So that was that."

Anti-Bullying Pro was founded in 2011 as part of the Diana Award and works to train young people in the UK to become anti-bullying ambassadors in their schools.

The organisation 'raises awareness of bullying behaviour and supports schools and young people to tackle it across the UK and beyond', according to their website.

GQ/YouTube

Evidently, Poulter was able to find some humour in the comparison and has seemingly taken the online memes in his stride.

When he shared a snap of his costume, Poulter wrote: "In addition to having a laugh at my expense I wanted to try and raise some attention for a cause I am an ambassador for! @antibullyingpro.

"As this month is Bullying Prevention Month in the USA and Antibullying Week in the U.K. is just around the corner, I would really appreciate it if you could please give them a follow before you like or share and help support the cause to make school a safer and happier place for young people."

The actor, who has appeared in films like The Maze Runner, Son of Rambo and The Chronicles of Narnia: The Voyage of the Dawn Treader, is starring in the new Guardians of the Galaxy movie in a pretty important role.

Guardians of the Galaxy Vol 3 was released in cinemas on 5 May.