Jessica Simpson hailed Eric Johnson as her ''perfect soulmate'' as the couple celebrated their sixth wedding anniversary.

The 39-year-old star has taken to Instagram to give fans a behind-the-scenes insight into their anniversary celebrations, holding up a giant, purple crystal butterfly that Eric gave her.

Jessica captioned the image: ''Eric Johnson, my Husband, I love you. 6yrs ago today I married my perfect soulmate. Our unity was written in God's sky of colliding stars. Together we manifest dreams, nurture desire, and hold space. Destined, it always has been and always will be, forevermore. Also, anyone who knows me at all knows that this crystal butterfly is my dream gift [butterfly emoji] ''Whatever our souls are made of, his and mine are the same.'' (sic)''

Meanwhile, Nick Lachey, Jessica's ex-husband, revealed earlier this year that he hasn't read ''a single word'' of her memoir, 'Open Book'.

The 46-year-old star - who was married to Jessica from 2002 until 2006 - insisted that he and his current wife, Vanessa, haven't taken the time to read the pop star's book.

He said: ''I have not read a single word.

''Both of us have not read the book, and no, she did not reach out before it was published.''

In her book, Jessica described Nick as her ''first love''.

The blonde beauty - who previously admitted to being a virgin before their marriage - wrote: ''Nick loved the fact I was so strong in my faith and that I had this wide-eyed innocent approach to life. When he proposed in 2002, I said yes.''

Jessica also insisted she remains respectful of her ex-husband.

She said: ''I was really young and my success hadn't really begun.

''He knew me as this young, innocent 18-year-old that had never been introduced to the world in so many ways. I went straight from my father to him. Nick's very smart. He was eight years older than me, but he was also young.

''We meant a lot to each other and we always will. I want to be very respectful because I married him for a reason and we were together for seven years for a reason. He has a family now and I would never say anything to disrespect that.''