Alexsandra Wright alleged in 2009 that Knowles is the father of her son Nixon, who was born in February, 2010.
A Dna test confirmed Wright's claim and Knowles was subsequently ordered to pay his former mistress $12,000 (£7,500)-a-month in child support.
Wright, who alleged Nixon was conceived during an 18-month fling with the music manager, has now asked a judge to increase the payments to cover security expenses, according to Tmz.com.
She claims she needs the money because Knowles sent her a "threatening" email in 2011. He reportedly wrote, "You hurt my family. There's a price to pay."