Channel with Conditional Fields

I am new to EE and this question may be very elementary to many experienced developers.

We are working on a directory type website that will have member logins. There are going to be two types of members - Standard and Premium. Within EE we are hoping to manage the registration data for the two types within the same channel. The way we would like to handle it is with a conditional fields. The first field would be a radio button for “Profile Type” and the options would be “Standard” and “Premium.” If the admin chooses the “Premium” option they would be presented the ‘default’ fields that both types of profile would use AS WELL AS the additional fields that only a “Premium” type profile would contain. Is this possible and if so how would this best be handled? Is there an add-on/plugin needed for this?