The 'Toxic' hitmaker played herself in a special episode of the musical drama - which aired in the US last night (28.09.10) - and the regular cast members were thrilled to have her on board for the show because they were such big fans of her music.
Naya Rivera - who portrays Santana - revealed: "I love Britney Spears. I mean, who doesn't? We all grew up with her. The first music purchase I ever made was ' Baby One More Time' on cassette. It was like, Britney Spears is going to be in my mitts, what do I do? And I was like, 'Hi Britney!' And then she was like, 'Hey!' She was awesome and beautiful. She was magical."
Heather Morris - who plays cheerleader Brittany - got particularly close to the singer in the episode, which was titled 'Britney/Brittany', and the 23-year-old actress admits she was in awe of her co-star.
She gushed: "I just sat there and stared at her. Like, 'Wow, I'm just hanging out with Britney Spears as Brittany the character. We're doing a scene. I'm singing her songs. It was weird.
"When I was younger she was, like, my idol. I am, like, literally an inch away from Britney Spears, who I used to watch on television and, like, learn dance moves to. ... It's Spearstacular."