The 'Boys' hitmaker will join the 'Delicate' singer and former Fifth Harmony star Camila Cabello on the road this June, and she's keen to debut a new track during her set.
Speaking on Apple Music's Beats 1 about the shows - which sees the girls perform two consecutive nights at Wembley Arena, Dublin's Croke Park and Manchester's Etihad Stadium - the pop beauty, from Cambridge, England, said: ''A stadium, that's like the size of the town where I am from.
''Now it's like serious. I have to put out a single.''
Admitting she's a little nervous, Charli - whose real name is Charlotte Aitchison - added: ''And it's sort of, like, scary, but more because there's all those expectations.
''Hopefully I'll put out a song before.''
The 'Doing It' hitmaker previously confessed she'll ''have to behave'' herself at the concerts as she is prone to swearing.
Though the 25-year-old singer is ''very excited'' to take to the stage, she admits she'll have to tone down her potty-mouth to avoid being labelled as the tour's ''bad influence''.
She said: ''I'm very excited about that. And I think it's so cool that Camila Cabello is also on the tour. I think it's gonna be such an epic lineup. I'm really, really excited about that tour. I think it's gonna be awesome.
''I really like, swear a lot when I'm on stage as well, and that just cannot happen. So I really have to behave.''
Taylor Swift's 2018 UK and Ireland tour dates are as follows:
June 8 and June 9, Manchester, Etihad Stadium
June 15 and June 16, Dublin, Croke Park
June 22 and June 23, London, Wembley Stadium Connected by EE