Essien, who had been sending threatening letters to the singer since 2009, has been warned to stay away from the 31-year-old star, a website reports.
Knowles had also won an anti-harassment order in court in 2011, prohibiting him from troubling her.
“Staff have been briefed on the situation and pictures of him have been passed round. They’ve been told to keep their eyes open and be extra vigilant,” a source said.
“Security has been increased on a few engagements now, especially for her (British) promo. It is believed similar letters to the ones that Essien sent have been received,” he added.
Photos: Shraddha Kapoor, Kim Sharma at 'Haseena Parkar' screening
Mumbai to Goa train: First look at the glass-top Vistadome coach
Shuttler Ashwini Ponnappa keeps it short and sexy on social media
Photos: Narendra Modi, others at Marshal Arjan Singh's funeral
Photos: Sussanne Khan and Nimrat Kaur spotted at a spa in Juhu