This post contains discussion of mental health issues.

If you're a Glee fan, you probably remember Britney Spears's memorable appearance in the Season 2 episode "Britney/Brittany" back in 2010.

Britney's appearance was filmed a few years into the conservatorship that her father Jamie had put her under earlier in the 2000s. She's since been freed from the conservatorship and has spoken out about its damaging effects on her mental health and general well-being.

In a recent episode of their podcast And That's What You REALLY Missed, former Glee stars Kevin McHale and Jenna Ushkowitz revealed what it was like filming with Britney during that time — and it sounds like it was a little rough.

During the episode, Kevin admitted that the cast and crew weren't "totally sure" whether Britney would actually show up for her day of filming. “We find out Britney is coming onto the show, and we can’t believe it," he recalled. "But it was also a little bit of ‘Is she going to come? Is she not going to come?’"

Jenna said that Britney was "very quiet and very nice," but also seemed "very nervous." "And…if you will, in the nicest way possible…a little vacant," she also admitted. "I mean that in the kindest way because at that point, she must have been going through so much.”

Kevin also pointed out that it was "sort of hard to witness" what was actually happening with Britney while they were filming. "It was great, and then she would get whisked away," he recalled. "Somebody from her team or something would take her away, and she’d come back and be again, for lack of a better word, a bit vacant.”

“It felt like she was not given the chance to participate in the way that she wanted to," he added.

Kevin went on to note that Britney was "amazing" on set, and that "she was fully in it" when it came to filming her scenes — but Jenna still described the experience as bittersweet.

“It was this very weird contrast of being so excited," she said, "and also, like, now I just feel sad thinking about what she was going through at the time.”

Listen to the entire episode here.

The National Alliance on Mental Illness helpline is 1-888-950-6264 (NAMI) and provides information and referral services; GoodTherapy.org is an association of mental health professionals from more than 25 countries who support efforts to reduce harm in therapy.