Income or expenses which arise in the current period as a result of errors or omissions in the preparation of the financial statements of one or more prior periods are called as Prior Period items.
Also, errors in the preparation of the financial statements of one or more prior periods may be discovered in the current period. Errors may occur as a result of mathematical mistakes, mistakes in applying accounting policies, misinterpretation of facts, or oversight.
Thus, the expenses incurred in the prior period need to be accounted for in the usual manner in the current period and then disclosed separately in the profit and loss account as prior period item.
Accounting entries would be:
Dr Expenses account
Cr Credit Card account
and then while making payment to Credit card outstanding bill
Dr Credit Card account
Cr Bank/Cash account
Of course you need to have bills to record the transactions.
The above treatment is as per Accounting Standard AS5