Kristen Bell loves her engagement ring.

The 'Forgetting Sarah Marshall' actress says partner Dax Shepard did a good job with the Neil Lane design, and she is very excited about her upcoming nuptials.

She said: "He nailed it! I'm just really excited. I'm happy and trying to live in that moment. It's kind of indescribable."

The 29-year-old star is preparing for her big day by taking up Pilates - a stretching exercise used by celebrities including Jennifer Aniston and Jamie Lee Curtis.

She said: "I really, really enjoy it. Stretching is involved, so it doesn't really feel like you're working out!"

Kristen is rumoured to be starting a family with Dax, and is building a nursery in her Los Angeles home in preparation.

A source said: "She's planning a bit. But it won't be long. They talk about starting a family all the time."

Kristen has previously vowed to put her family ahead of her work in Hollywood, saying: "I think your significant other should be way more important than your work, personally. I love working. But I don't know that I'd say I'm a workaholic because I also love maxin' and relaxin'."