Justin Timberlake was first linked with Jessica Biel back in January after his split from Cameron Diaz.
It is believed that after four months together, the 'Sexyback' singer is in love with Biel.
A source told People, "Justin's in love. She's the coolest chick ever. He wants to be with her all the time. He's ready to be serious."
Timberlake, 26, and Biel, 25, were spotted dining together at a restaurant in Manchester last week.