The Hills star Spencer Pratt says he won't hold anything back

Spencer Pratt is working on a tell-all book about his marriage with estranged wife Heidi Montag.

The Hills star, 26, will also open up about his relationship with mother-in-law Darlene Egelhoff.

‘My last book How To Be Famous didn’t make the New York Times
best-seller list because it was in the self-help section,’ Spencer tells Us Weekly.

‘This one is going to be totally different. I’m not holding anything back.’

But Heidi – who had 10 plastic surgery procedures in one day in November – isn’t too pleased about Spencer‘s plans. 

‘Right now I’m looking into my legal options,’ she tells TMZ.

Heidi, 23, and Spencer announced their split in June and she filed for divorce last month, citing irreconcilable differences.

They got married in California in April 2009.

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