Mila Kunis is pregnant.

The 30-year-old actress is expecting her first child with her fiancé Ashton Kutcher, 36, to whom she recently got engaged to following two years of dating.

A source told People magazine: ''They are both very, very happy. It's still early.''

The loved-up couple sparked engagement rumours last month after the brunette beauty was spotted sporting a diamond sparkler on her wedding finger in Los Angeles.

However, the pal close to the pair insists their baby news won't encourage them to rush down the aisle.

The insider added: ''It won't necessarily be a short engagement. They haven't begun planning the wedding yet.''

The duo began dating in 2012, after Ashton split from his ex-wife Demi Moore, but they have known each other for years after playing opposite each other in hit 1990s sitcom 'That '70s Show'.

Meanwhile, it is believed Ashton had developed a crush on his co-star during that time on the programme, but their romance didn't blossom until years later.

A source previously said: ''He was so in love with [Mila] for a while when they worked together. He thought she was a goddess, was always talking about how beautiful she is.''