'After' Cast Praises Co-Star Selma Blair, Who Filmed Movie While Battling MS (Exclusive)

"She's a bucket full of sunshine and olives and everything good and nice."

Selma Blair's co-stars are praising her strength following her multiple sclerosis diagnosis.

ET's Courtney Tezeno caught up with some of the stars of After earlier this month, and they couldn't help but gush about Blair, who plays the leading lady's mother in the film, and was diagnosed with MS last year. After follows a sheltered Tessa as she goes away to college and falls for the bad boy, Hardin.

"She's wonderful. She's a bucket full of sunshine and olives and everything good and nice," Josephine Langford, who stars as Tessa, said. "She's hilarious and she's lovely and she's great as an actor."

Langford's onscreen love interest, Hero Fiennes-Tiffin, lamented that he didn't get more scenes with the Cruel Intentions actress, but had plenty of praise for her regardless.

"She's so cool. We had, like, a hour or two conversation outside," Fiennes-Tiffin said. "... When you see actors who are so funny and confident and just great people and when they say action they're straight into the role and straight out of it and it's just inspiring really."

Likewise, Inanna Serkis, who stars as the villainous Molly, said Blair is "so sweet."

"I love her... She was getting her makeup done the same time that I was and I was like, 'I just really need to come up and say that I love you and you're awesome.' She was like, 'Thank you!'" Serkis recalled. "I didn't do any scenes with her, but she's so sweet. I honestly love her... She's the sweetest."

While Shane Paul McGhie didn't get the chance to meet Blair on set, he still had lovely things to say about her.

"I never got the chance to actually meet Selma, but she followed me on Instagram one day and I was like... 'Sorry that must have been the fan page.'... And then I saw the blue check and was like 'Oh my God,'" McGhie, who plays Landon, Tessa's best friend, said. "... She just exudes this very warm, positive, energy and I would love to give her, like, a really big hug."

As for director Jenny Gage, she said she's been a fan of Blair's for years.

"She's an incredible actress," Gage said. "I've loved her since I was a 20-year-old girl myself. She's so professional, so passionate and now we see her on this journey. She's such a strong, incredible woman and such a force that it's been great having her on the movie and knowing her afterwards."

The kind words for Blair come after she revealed her MS diagnosis last October. In a February article published in Vanity Fair, Blair, who filmed After while battling the disease of the brain and spinal cord, admitted that she was concerned she'd be unable to act following her diagnosis.

"I don’t know if I believed in myself or had the ambition before my diagnosis," Blair said of continuing her career, which is marked by films including Cruel Intentions, Legally Blonde and The Sweetest Thing. "And oddly now I do, and I don’t know if it’s too late."

After hits theaters nationwide on April 12. Watch the video below for more on the flick.