Millie Bobby Brown "collapsed to the ground" watching Taylor Swift perform live.

The 'Stranger Things' star and her sister are huge fans of the 'Anti-Hero' hitmaker and even have a board where they "like to cross out the songs that she's done" so they can predict "what she's going to do next".

Appearing on 'The Kelly Clarkson Show', she told the host: "When I went to my show, I went to Ohio. I flew there solely for Taylor, and she played 'Evermore', and I collapsed to the ground.

"It was pretty crazy, but it was an amazing experience."

The 20-year-old actress admitted she is a "hardcore" Swiftie, even as host Kelly joked "some might call that a stalker" given the level she goes to.

Millie quipped: "I am like hardcore. Like, I know exactly where she is at all times kind of thing."

She insisted she is "the same as" the other fans at Taylor's concerts, and she had an absolute blast at the 'Eras Tour'.

She added: "I love Taylor Swift. I went to the Eras Tour, and it was the most amazing experience. The fans there are the same as me. We love her that much."

Millie even used a lyric from Taylor's song 'Lover' to announce her engagement to Jake Bongiovi in April last year, as she shared a photo of herself wearing a diamond ring as her fiance hugged her on the beach.

She captioned the snap on Instagram: "I've loved you three summers now, honey, I want 'em all."

Millie got Taylor's stamp of approval as she liked the post.

The couple have been busy planning the big day, and she feels "very blessed" to be getting so involved in the whole process.

She recently told Entertainment Tonight: "It's been really excited. I'm very, very blessed and very lucky."