“Simpsons” co-creator Sam Simon made millions laugh through the famous Fox cartoon series. But the entertainment world got less funny after it was revealed the funnyman died from colon cancer Sunday in his Los Angeles home.

Girlfriend Kate Porter was just one of the people saddened by his death. The makeup artist took to Twitter to mourn Simon. “Last night I lost my best friend, my love, my hero, my everything. My heart is truly broken. I will miss you. Iu [sic],” she tweeted Monday.

Porter shared a photo of herself and Simon embracing. Both had smiles on their faces. The message was shared 46 times and garnered 90 favorites from her 795 followers.

The day he died, Porter shared another photo of the couple together with a similar message: “My hero, my love and my best friend @simonsam.”

She describes herself as a celebrity makeup artist from “Hollyhood,” California, and is the owner of Beauty Katering.

The makeup artist shared several tributes that were written for her boyfriend. One was from screenwriter Mikko Alanne. “Farewell dear beautiful Sam. You are my hero & inspiration and I will miss you always. Your life changed the world,” he wrote.

Another person shared a collage of photos of Porter and Simon. It didn’t have a caption, but simply tagged Porter.

Simon was an activist who reportedly became involved with animal rights after he was diagnosed with colon cancer in 2012. He was only given three to six months to live at the time. Ex-wife Jennifer Tilly said the diagnosis made him a better man.

"Since he became sick, it's like his vision has expanded. I hate to say this, but little things used to bother him. He was always a very Type A personality. And I think he realizes that a lot of things that maybe would make him crazy, they're just not important. He's discovered what's important in life. Such a difference. A lot of the stuff he does he doesn't even talk about,” she said in September 2014, according to celebrity blogger Perez Hilton.

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