Jessica Simpson Says She Got Pregnant For The Second Time Because Her Boyfriend, NFL Star Eric Johnson, Didn't Use A Condom

Jessica Simpson said she didn't know how she was possibly pregnant after giving birth to her first child six months ago. Then she remembered her boyfriend Eric Johnson didn't use a condom. 

On an interview with Ellen DeGeneres, set to air Wednesday on "The Ellen DeGeneres Show," Jessica Simpson said, "I don't know [how it happened]."

"Apparently protection with thrown out the window," Simpson told Ellen.

Jessica Simpson began dating former NFL tight end, Eric Johnson in 2010. The two announced their engagement later that year.

Last May, Simpson gave birth to the couple's first child, a daughter named Maxwell Drew Johnson.

Six months later, the singer found out she was pregnant with Eric Johnson's child for the second time.

"We were definitely extremely shocked," Simpson told Ellen.

During the first pregnancy, Simpson told Ellen that she felt "amazing." "Like, I could do everything, eat everything. Do whatever I wanted. I had a lot of energy."

Now that she's in the midst of her second pregnancy, Simpson admitted to feeling "exhausted." She even said Tums have become her favorite snack.

The "Fashion Star" judge confirmed her second pregnancy on Christmas Day after Access Hollywood broke the news last November.

Though Jessica and Eric have yet to wed, Simpson says Johnson is extremely supportive. Losing the weight from the pregnancy was tough, Simpson recalled, but she knows she can get through it with the support of her soon-to-be husband.

"Apparently Eric still wanted me so...I can gain as much weight and I will have a husband-to-be that loves me!" She said.

Johnson's best year in the NFL came in 2004, when he led the 49ers in receiving with 82 catches for 825 yards and two touchdowns, according to NFL.com. He retired in 2008 after being released by the New Orleans Saints.