adding new column to the table that is already replicated

i have a script that is going to add new column in a table that has millions of rows.

if not exists (select * from syscolumns where id=object_id('progressnote') and name='dModifiedDate')
   alter table progressnote add dModifiedDate DATETIME NULL
GO   

so this table is also replicated to other server,

what steps do i need to take to make sure replication does not break its synced properly and what about adding new column into a huge table?

Regards

k