(Cover) - EN Showbiz - Kim Kardashian thinks her engagement ring is the "most beautiful thing" she has ever seen.

The reality TV star announced she is to marry professional basketball player Kris Humphries today.

Kris, 26, who has been dating Kim for six months, proposed with a 20.5 carat custom-designed ring.

"It's the most beautiful thing I have ever seen," Kim told People of the ring estimated to cost $2 million. "It's perfect."

Kris is delighted his fiance is pleased with the band, explaining he had one clear goal in mind when buying it. "I just knew I wanted it to be big," he laughed.

The ring features a 16.5 carat emerald cut stone in the middle which is surrounded by a pair of two carat trapezoids, weighing a total of 20.5 carats.

Kris designed the ring with jeweller Lorraine Schwartz, who is responsible for other celebrity engagement bands, including Beyonc Knowles' and has been close to the Kardashian family for many years. "I knew she'd love it - she better!" Kris said.

Kim wanted a classic design that was not identical to her sister Khlo's radiant cut diamond.

"[Lorraine] always listened to what I would want and the shapes I love," she said. "I had said I loved an emerald cut and they were scheming and plotting for a while."

The couple plan to marry this summer and Kim is already thinking about having children. "We talk about it [having kids] all the time," she said. "Kris is just as close to his family as I am to mine. In the next year we want to maybe try to start a family."

Sister Khlo - who is married to Los Angeles Lakers basketball player Lamar Odom - expressed her joy at her sister's news on Twitter. "Congratulations to my beautiful big sister Kim on finding the love of your life! Seeing you this happy makes all of us BEYOND happy and my face literally hurts from smiling (sic)," Khlo tweeted.

Kim's sister Kourtney was equally thrilled. "My sister is engaged!!! I'm squealing with excitement! The princess has found her prince," she tweeted. (C) Cover Media