Or no you have to first get FAA PPL based on your foreign license and then do some training and get CPL and then ATP?
The entry requirements for the CPL or ATPL course/exam in most countries is that the candidate holds a PPL (or higher). That doesn't have to be a specific PPL - any ICAO PPL (or higher) will do just fine.
So when you, for instance, have a JAR-FCL/EASA PPL (which is ICAO compliant) and you want to obtain an FAA license, you've basically got three choices:
- Get a piggyback FAA PPL. This will be based on, and is dependent on the validity of your foreign PPL, but is relatively easy to obtain.
- Get a standalone FAA PPL. You're essentially starting from scratch; only the previous flying experience counts. But you need to do the written and the flight test, and the CFI has to sign you off as being ready for the flight test, which usually takes a few flights before he's convinced.
- Get a standalone FAA CPL (or ATPL) where your JAR-FCL/EASA PPL is proof of having met the entry requirements for the CPL/ATPL course/exam. You will need to do the full CPL/ATPL course for this, obviously.
AFAIK there are no solo elements in the CPL course so the whole course is done as PU/T, with the instructor as PIC (or whatever the FAA equivalents are called). Therefore it doesn't matter that your JAR-FCL/EASA PPL is not valid for flight on an N-reg, and there's no need to get a piggyback PPL just so you can do the CPL course.