I have both UK and US accounts…as @andrew_fishy said, apply, but with a different email (!) to your UK account and US Phone #, then message then in app. You will need a US mailing address for them to send you the card in the US. Once enabled, you have both of them visible in the app.
Just an FYI…many company’s are global but will completely mess up if you use the same email…have learned the hard way. E.g. Exprian, Transunion, etc. are all global company’s but you may have had accounts with them in the US already. Before you try to sign up with any of them for your UK history, etc. use a UK specific email.
Good luck!