The 23-year-old singer performed his band's first big hit at the opening night of his US headline tour at the Masonic venue in the Californian city, and whilst he attempted to mix up the speed of the song, his fans could be heard over him belting out the ''na na na na'' part just like the original.
Whilst the majority of Harry's set was songs from his eponymous titled debut solo album, including 'Sign of the Times', 'Sweet Creature' and 'Two Ghosts', the dark-haired hunk made sure to pay homage to where his career began, also performing 1D's 'Stockholm Syndrome'.
Harry didn't speak much throughout his set, but early on he declared his fans his best friends.
He said: ''You are the best friends any person could ever ask for.''
Other than Harry, his band mate Niall Horan has been doing 'Fool's Gold' at his solo shows.
Liam Payne has completely turned his back on the group's music and recently confessed that hearing 'What Makes You Beautiful' is embarrassing as he's more ''mature'' these days.
He said: ''When the DJ puts on 'What Makes You Beautiful' you get a bit shy about it. It's a different maturity, of course we were very young when we did that.''
Harry, Niall, Liam and Louis Tomlinson went on an indefinite hiatus in March 2015, but have each launched their own solo careers.
'Carolina' hitmaker Harry brings his world tour to the UK later this year.
Harry's 2017 UK tour dates are as follows:
October 29 - London, UK - Eventim Apollo
October 30 - London, UK - Eventim Apollo
November 1 - Manchester, UK - O2 Apollo Manchester
November 2 - Glasgow, UK - SEC Armadillo
Labrinth has teamed up with Sia and Diplo to form a new supergroup: LSD.
The Struts teamed up with Kesha for a red and gold themed music video as part of their collaboration on 'Body Talks'.
Brody Dalle's band dropped their first new music since 2003's 'Coral Fang'.
Sometimes actors are not acting.
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