Jessica Simpson threw a carnival themed bash to celebrate her daughter's first birthday.

The 'Fashion Star' mentor and her fiance Eric Johnson - who will welcome a son in July - invited friends and family to an outdoor party at their Los Angeles home to wish Maxwell a happy birthday on Sunday (28.04.13).

A source told Us Weekly: ''They had '70s and '80s music playing on the speaker. Everybody was having a great time being outside.

''Kids were swimming in the pool with a lifeguard watching, and many of them were swinging on swings and playing on a teeter totter.''

Jessica, who ''wore a floral tunic and looked great,'' was joined by her younger sister Ashlee and pregnant best friend CaCee Cobb at the party.

The source added: ''They all hung out together.''

Meanwhile, Jessica recently revealed Maxwell is closer to her father than Jessica so she is hoping her second child - which she knows to be a boy - will develop a special bond with her and become a ''mamma's boy''.

She said:''Maxwell is definitely a daddy's girl. If he's in the room she doesn't want anyone else to hold her. So I hope my son will be a mamma's boy.''