Lauren Conrad thought she was having a ''giant baby''.

The former 'Hills' star gave birth to Liam James Tell - her first child with husband William Tell - last month and she was amazed at how ''tiny'' the 6lb 14oz tot was when he was born because she hadn't even bought baby clothes in the smallest size as she was so convinced he'd be huge.

She told People magazine: ''Before the delivery, I felt like I was getting ready for a blind date.

''We considered doing the 4D ultrasound but then decided to wait. I just remember thinking he was so cute - and I was surprised by how tiny he was.

''I was convinced I was having a giant baby, to the point where I didn't even buy newborn clothes - in my head he was 9lbs.

''He definitely looks like William. But he's still so tiny it's hard to tell.''

She also revealed the couple opted to find out the sex of their child because she doesn't enjoy being surprised.

She said: ''I don't really love surprises. I like to have all the information. And I was sharing my body with someone - so I wanted to know as much as possible about him.''

And Lauren was delighted to find out she was expecting a boy because she'd always wanted a son.

She added: I always hoped I would have a boy. Boys are so fun. I was a tomboy, and I always play best with boys. When we found out, I was so excited.''

While little Liam is still only a few weeks old, his famous mother is already ''stressing out'' at the thought of him getting bigger.

She said: ''I'm already stressing out because I want him to stay this tiny and I know he won't.

''So I'm just trying to enjoy how itty-bitty he is. I was looking at him the other day, and I was like 'I understand now why people keep having babies!'

''We'll probably have two. I think it's best not to be outnumbered.''

She also admitted she cannot wait to watch Disney films with her son.

Lauren said: ''And I'm just excited to play again! I can't wait to break out the finger paints.

''And I'm such a Disney nerd, so I get to watch those movies with someone who is seeing them for the first time.''