According to The Associated Press, the massive rock, which Temple's father bought for the actress for her 12th birthday in 1940, will hit the auction block April 19 at Sotheby's "Magnificent Jewels" event in New York. The cushion-cut stone is set in platinum with diamonds, and the auction will also include a gold setting for the ring.

>> Click here to see Sotheby's Facebook post

"This was a treasured piece of jewelry that she wore and enjoyed her entire life," Frank Everett, a Sotheby's sales director, told the AP.

>> PHOTOS: Remembering Shirley Temple (1928-2014)

The ring is expected to sell for $25 million to $35 million, the AP reports.