There's no bigger gangster than Uncle Sam: When you owe him money, you have to pay.

Which is why Trey Songz is in a bit of a jam. According to TMZ, he owes the IRS $748,870.08 on his income from 2013.

The way these things typically go, it wouldn't surprise us if he eventually gets hit with a similar lien for 2014.

Trey had to have made a lot of money in 2013 to rack up such a tax bill, and hopefully he has enough of it saved to make right with the government.

And he really needs to get a new accountant.