The 'Eez-eh' hitmakers will be headlining the Glastonbury festival alongside Arcade Fire and the legendary heavy metal band next week and they think the group are a ''controversial'' booking.
Serge said: ''Metallica, they're massive. I'm being entirely honest with you, I don't really know their tunes but they're massive.
''They've been doing it for a long time, so they'll have a few tricks up their sleeves. It's been quite a controversial choice but I think that can also work in your favour. I've met Lars [Ulrich], the drummer. He came to a show of ours in San Francisco and was a lovely chap, so I wish him all the best.''
However, the band - also made up of Tom Meighan, Chris Edwards and Ian Matthews - have been checking out Arcade Fire and are a fan of their album 'Reflektor'.
Serge told NME magazine: ''I've only seen little bits of pictures and stuff but they seem like their live show is interesting. They seem like a great band for a Friday night.''
The actress thinks it would be tough to recast her character, Winifred Sanderson.
Beck wishes he'd had ''more fun'' when Kanye West invaded the stage in protest at his 2015 Grammy Awards win.
The Duffer Brothers wanted to "experiment a little bit".