R. Kelly has a “put it on my tab” approach to his taxes … because TMZ has learned his ever-expanding tax bill has just increased by more than a million bucks.

According to documents filed in Illinois, the “Trapped in the Closet” singer owes Uncle Sam a cool $1,379,695.11 for unpaid taxes for the year 2011.

As TMZ first reported, Kelly already owes $4,848,072.71 in unpaid taxes for the years 2005-2010. That brings his total to a cool $6,227,767.82.

Seems his accountant has been trapped in a closet for the past seven years.

A rep for Kelly tells TMZ, “He takes this very seriously and is already communicating with the IRS about the payment process to quickly resolve the issue.”

Read more from the Source: TMZ.COM