The former 'Brady Bunch' actor and the 'America's Next Top Model' winner - who met in 2005 and married a year later - split in May but now Christopher has filed for divorce, citing "irreconcilable differences".
He said: "The agreement for divorce was a mutual one, and yes, Adrianne knew that I was going to serve her with papers."
Their representative told 'E! News': "The couple is still friends and the process thus far is very amiable. I again ask for everyone to respect their privacy as they work through this delicate period in their lives."
This was the third marriage for Christopher - who played Peter Brady in the 70s TV show - and the first for 29-year-old Adrianne.
The couple do not have any children together.