Although both Jessica Simpson and Nick Lachey deny infidelity as a reason of their split, it seems that things weren't exactly right.

According to recent rumors Simpson had a secret affair with Maroon 5 singer Adam Levine back in 2004, when she was still claiming to have a happy marriage with Lachey.

Two eyewitnesses, photographer Andrew Sweeney and reporter Lisa Ladabouche, claim they spotted Simpson and Levine extremely close, just after they both performed at a concert for radio station Kiss 108 FM in May 2004.

Jessica attended the concert alone, while Nick was on holiday in Fiji with his brother.

Sweeney and Ladabouche told US Weekly: "They were backstage flirting. He was touching her hand and then they just leaned in and started going at it, making out. Not horribly, like teenage making out, but like adults, little kisses."

"It was a shock, especially knowing her husband was away and she's supposed to be this innocent figure."