'I'm outside. Answer the door.' Selma Blair and Christina Applegate's decades-long friendship.

Twenty years ago, Christina Applegate and Selma Blair starred in a raunchfest about sex, romance and penis jokes. But the sweetest thing about 2002's The Sweetest Thing was always the female friendships at its core.

In the film, Applegate and Blair played friends of Cameron Diaz's Christina. 

They support each other's conquests, help each other out of sticky situations and uh, perform a song about big penises in a restaurant. 

Two decades after The Sweetest Thing's release, Applegate and Blair's friendship is just as enduring.

Watch: Selma Blair talks about her MS diagnosis. Post continues below video.

In November 2022, Applegate received a star on the Hollywood Walk of Fame. 

It was her first public appearance since being diagnosed with multiple sclerosis (MS) in mid-2021 and Blair was in attendance at the emotional unveiling ceremony. 

The pair have been publicly supportive of each other in recent years, especially in regards to their diagnoses of MS, a chronic disease that affects the central nervous system.

Blair was diagnosed in 2018 and has been open in sharing her experiences on social media.

In a November 2022 interview with Entertainment Tonight, Blair spoke of their friendship.

"Oh gosh, I've known Christina for so many years, we're really close, and I'm just a fan of hers," Blair said. "She is an iconic California girl actress of my generation, and she is it. There has not been one thing that she's done that I haven't been like, 'Nailed it,' and she's nailing just being who she is with this MS."

Blair said her friend being honoured was a moment she was proud to be a part of.

"She was funny and definitely like her performance was amazing," she told ET of Applegate's Walk of Fame speech.

"But to be there - I just wanna witness the greats in my friends' lives, like just quietly back there, and so to know that I was there for something that we dream about when we're little."

Image: Getty.

Asked how she had supported Applegate following her MS diagnosis, Blair said that the support went both ways.

"Christina still supports me. She's just a strong one," Blair said. "She really is. She's such a nurturer. If you need something she's at your house. There have been things that I had been unglued, and she's like, 'I'm outside. Answer the door.' She's just amazing and strong and fun.

"But I'm more like, 'OK, if you need help with canes,' and that stuff, 'cause I'm like, really into all of that, like all the things that help me get around, but she's getting it locked down. 

"She has a lot on her plate. It's a lot, but she's as brilliant and beautiful as ever."

In May 2022, Blair released her memoir Mean Baby: A Memoir of Growing Up which documented her childhood, alcohol addiction and experiences in Hollywood, as well as the aftermath of her MS diagnosis.

On Twitter, Applegate congratulated her "MS sister" on the release.

Get it. Congratulation MS sister pic.twitter.com/UlsCPVXr82

— christina applegate (@1capplegate) May 20, 2022

In October 2021, Blair's documentary Introducing, Selma Blair was released. It followed Blair adapting to new ways of living after learning of her diagnosis.

Applegate again praised her friend, imploring her followers to watch the film for insight into what life with MS is like.

"Being technically disabled is what it is," she tweeted. 

"I didn't know what MS was before I had it. My life is changed forever. But my girl Selma Blair documented the first year. Which is hard. Please watch her documentary. Introducing, Selma Blair. An intimate look inside a person with MS."

Though they worked together many years ago, the pair have their children to thank for their enduring relationship.

In a March 2018 reunion to talk about The Sweetest Thing with Entertainment Weekly, Blair, Applegate and Diaz said that they had not reunited as a trio, but Blair and Applegate saw each other regularly because their kids were friends.

Applegate's daughter Sadie Grace LeNoble and Blair's son Arthur Saint Bleick are both 11.

When Applegate shared her MS diagnosis in August 2021, Blair referenced their children in her message of support.

"Loving you always," Blair tweeted to Applegate. "Always here. As are our kids. Beating us up with love."

"I love our two weirdos," Applegate responded. "They are so fun."

Feature image: Getty.