Lauryn Hill is facing federal charges for tax evasion, NY Daily News reports. 

The songstress, who had a surprise appearance at Summer Jam last weekend, has been charged with willfully failing to file income tax returns with the IRS for the years 2005, 2006 and 2007. Authorities say that Hill earned more than  $1.8 million during that period, with a lot of her income coming from royalties through music and film.

If she's convicted she could face prison time for up to a year, plus hundreds of thousands of dollars in fines.