Mosh to a specifing remote shell

With ssh, I can do something like the following:

ssh user@host -t /path/to/some/shell

How can I automatically launch a shell on the server with mosh ?

I have tried with

mosh user@host -ssh /path/to/some/shell

and with:

mosh user@host -ssh "ssh -t /path/to/some/shell"

with no luck. Is this at all possible?