Nikki Reed and Ian Somerhalder "really wanted a baby".

Nikki Reed and Ian Somerhalder

Nikki Reed and Ian Somerhalder

The 28-year-old actress and the 'Lost' star announced they are expecting their first child together last week, and the brunette beauty and her hunky spouse have reportedly always been desperate to start a family.

An insider told Us Weekly magazine: "Nikki said she always knew she wanted to have kids before she turned 30."

The couple - who got married in 2015 - are happier than they've ever been, especially now that their dreams have been answered.

The source added: "They are incredibly happy together. Ian worships Nikki. He's so sweet to her and treats her like a queen!"

The 'Twilight' star took to her Instagram account on May 4 to announce their happy news.

Alongside a picture of Ian kissing her baby bump, Nikki wrote: "Hi Little One, I know you, but only because I feel you. How is it possible to love someone so much already?

"All I know for sure is it's the strongest feeling I've ever felt. We've been sharing this body for quite some time, and we've already experienced so much together. We can't wait to meet you ... Love Your parents (sic)"

Ian, 38, subsequently shared the same snap on his own Instagram account and revealed the couple had tried to keep the pregnancy news to themselves for "as long as possible".

The 'Vampire Diaries' actor explained: "In my 38 years on this earth I've never experienced anything more powerful and beautiful than this. This has been the most special time of our lives and we wanted to keep it between the three of us for as long as possible so we could enjoy this time with each other and our little one who is growing so fast ... because that's what they do, they grow so fast."