Is it correct to write 'Felix's party'?

[GabrielOak]

Silly question, but is this correct?

E.g. Thank you for coming to Felix's party.

With the 'x' at the end making the 'ssss' sound I'm having doubts

Thank you

Felix's is correct.

Yes, that's right.

Thank you!

Yes.

(I know I'm too late)