After a long battle with cancer, LazyTown actor Stefan Karl Stefansson has died at 43, TMZ reported Tuesday.

A spokesperson for the Stefansson family told the publication that the actor passed away Tuesday surrounded by friends and family after a two-year battle with bile duct cancer. He and his wife had four children, according to his actor bio.

The Icelandic actor played Robbie Rotten on the popular Nick Jr. show for a decade alongside actress Julianna Mauriello, who played Stephanie. Stefansson last appeared on the show in 2014 during its series finale.

The actor made headlines when he was first diagnosed with cancer in 2016, but after undergoing surgery appeared to be on the mend. In 2018, however, the cancer returned and was inoperable, his family revealed.

In a social media statement in March, Stefansson said, "It's not until they tell you you're going to die soon that you realize how short life is. Time is the most valuable thing in life because it never comes back. And whether you spend it in the arms of a loved one or alone in a prison-cell, life is what you make of it. Dream big."

His wife Steinunn Ólína Þorsteinsdóttir also gave an update on his health in a public post on Facebook in March, writing, "Last Friday we got confirmed after a trip to Köben in Jáeindaskan that there are new metastases in Stefán that can not be removed by surgery.

"Even though I knew for a long time that this day would come, it's a difficult turning point. There is no cure for this," she continued. "Now he will have to undergo chemotherapy to try to prolong his life and we hope that this will go as well is possibly can, to improve how he feels and to prolong his life. The first medication was yesterday."

Fans of the show, which is popular in meme culture, took to Twitter to mourn Stefansson.

If you guys haven't heard Stefán Karl Stefánsson (aka Robbie Rotten) has unfortunately passed. We'll all miss this great man, he truly was number one. pic.twitter.com/qCRXRvfBR1 — PTSDGuts (@PTSDGuts) August 21, 2018

rest in peace robbie rotten — toby (@pobbbler) August 21, 2018

Robbie Rotten was always my favourtie part of Lazy Town. As the "We Are Number One" meme blew up, I listened on repeat for hours. Seeing Stefán embrace the meme and learning who he was as a person, I was inspired. Goodbye Stefán. You will always be #villainnumberone — Chase Dobson (@chase_dobson) August 21, 2018

ROBBIE ROTTEN DIED NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO — Sneaky (@SneakydaTrainer) August 21, 2018

RIP Robbie Rotten. Number 1 for multiple generations //t.co/uQ8cN5P83j — Hairo (@HighRiskOculus) August 21, 2018

I knew of Lazy Town and Stefan Karl, way before Meme Culture turned his character, 'Robbie Rotten' and the song, 'We are Number One' into a living legend. But it those memories of now and before which we will remember. Rest In Peace, Stefan, you were one of a kind! #StefanKarl //t.co/EA4one8ga3 — Joshua Wareham (Spyro Fanatic) 💎🔥🐉 (@Joshua_Wareham) August 21, 2018

RIP to Stefansson.

Photo credit: Nick Jr