On Monday's "Elvis Night," Blair, 50, danced to "Jailhouse Rock" with her pro partner Sasha Farber — and caused her best friend in the audience, Sarah Michelle Gellar, to get emotional.
"First of all, to be dancing to Elvis, to keep a smile on my face because I genuinely am so happy, and have Sarah here who's been with me from my first-ever movie in Hollywood," the actress said to reporters after the show, "And [for Gellar] to come to something like this 25 years later and give me love, I mean we're best friends, but to work out with her schedule and everything, and to have Sasha who's so wonderfully teaching me art of a better balance, it's all glorious to me."
She continued, "So I'm so happy, and so happy to get to have another week."
The Legally Blonde star's run on the show has already been an emotional one. During Blair's first week, she brought fans and the judges to tears with her moving performance.
disney+ Sarah Michelle Gellar crying at Selma Blair's performance on DWTS
"That's such a gift to inspire anybody," she said Monday night. "That is not something in my life I ever thought I would do. And I think with perspective, being a mom and growing older and really valuing my sobriety and things, that being vulnerable has really been a gift to me because I think I do have a lot of relatable human issues that so many people have. But I'm also someone that gets to be in a spotlight, and so I just roll with that and I'm learning to roll with it better."
Blair's Elvis-night routine even featured a cartwheel — an acrobatic move that she thought she'd lost the ability to do.
"That's something I could not do," Blair said. "I've been trying for so many years since that really big flare that set me back of MS. And to be able to invert and do it and just calm enough to go into a split without having my body go into some spasticity just gives me confidence that there's so many things to still try and do in life and can improve ... I never thought I'd be able to stand on a dance floor and do a jive. Even before MS."
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Sarah Michelle Gellar told PEOPLE exclusively before the season began that she was "of course" excited to see Blair compete on the reality competition series — and promised she "will be begging" for votes on her friend of nearly 25 years' behalf.
"What's the word when you're like, 'I'll be out there looking for votes for her?'" Gellar, 45, said at the time. "Shilling — shilling for votes. That was what it was!"
Dancing with the Stars airs Mondays at 8 p.m. ET on Disney+.