Rumor Mill: Justin Timberlake Cheated on Jessica Biel?

Justin Timberlake and Jessica Biel are at the center of a tabloid whirlwind, as Us Weekly’s cover story this week purports that Timberlake cheated on Biel with Olivia Munn last month.

According to the report, Timberlake and Munn had a three-day fling in New York City after meeting at a MySpace party in late September. An Us insider states that Timberlake “started chasing” Munn and eventually, but she resisted due to his involvement with Biel.

Celebuzz has reached out to reps for both Biel and Timberlake for a comment/denial, but have not heard back yet.

The source claims Timberlake told Munn his days with Biel were over, and the Daily Show beauty eventually gave in to his advances.

Timberlake and Biel began dating in 2007 about a year after he split from Cameron Diaz. Rumors of possible engagements, break-ups and troubles have followed the couple throughout the years, and they’ve kept their relationship on the private side because of the constant speculation.