Reese Witherspoon's fiance designed her engagement ring himself because he wanted it to be unique.

The actress announced her engagement to boyfriend of almost one year Jim Toth last week and friends have revealed the Hollywood agent insisted on a rare diamond to show Reese how much she means to him.

Jim chose the Ashoka diamond because of it's rarity and then worked with jeweller William Goldberg to design the perfect ring for his bride-to-be.

A source told US magazine: "Jim wanted it to come from him and for it to be completely unique."

40-year-old Jim took his time to select the perfect ring, he was reportedly spotted in several Hollywood stores looking for the perfect ring to propose to the beauty with last September.

A source said at the time: "Reese wasn't with him, because he wants it to be a surprise. But he knows her style. The Ring will be classic and beautiful, just like Reese herself."

Reese has previously dated 'Brokeback Mountain' star Jake Gyllenhall and has two children, Ava, 10, and six-year-old Deacon with former husband Ryan Phillippe.