The 29-year-old singer and actress gave an update on Britney, 38, during Thursday's episode of Good Morning America.
When asked how Britney is doing, Spears said her sister has faced challenges in 2020, like so many others.
"I think that she's doing just like the rest of us. She's trying to make the best and stay positive during a very challenging time, a challenging year," she said. "I think that's kinda the theme of everyone now."
Britney entered into a conservatorship more than a decade ago after experiencing mental health struggles in 2008. Her father, Jamie Spears, served as conservator until 2019, when he was replaced by Jodi Montgomery.
A judge recently ruled that Britney's conservatorship will remain in place until Feb. 1, 2021. In August, Spears was named the trustee of her sister's fortune.
"It was very, very hard, especially during these times, because shooting something with more than one person is very challenging during COVID," the actress said. "We had one day to get it done. Most everyone was able to make it."
Spears performed "Follow Me (Zoey 101)" on GMA.
Spears played Zoey Brooks on Zoey 101, which had a four-season run on Nickelodeon from 2005 to 2008. She will reprise the character in an upcoming revival.