Jessica Biel says becoming a mother has made her ''crazy''.

The 35-year-old actress welcomed son Silas with husband Justin Timberlake two years ago but admitted that motherhood can be extremely stressful.

Speaking to Australia's Daily Telegraph, she said: ''This might sound really terrible, but it's the truth. Having a child, I have never experienced more emotions in all my life, anger being one of them.

''Simply put, sometimes your two-year-old makes you crazy.''

Jessica also recently revealed that Silas is in the middle of his ''terrible twos'', and admitted his tantrums can be ''tough''.

She said: ''There's a lot of 'No' going on in my house ... It can be tough.''

Meanwhile, Jessica has insisted she knew she would marry Justin, 36, after ''a little bit'' of dating.

Whilst she can't recall a ''tangible moment'' in which she knew Justin was the man of her dreams, she admits it didn't take long for her to see a future with him.

She said: ''We had been dating for a little bit ... There was just a moment when I called a girlfriend and I said, 'I'm going to marry this guy.' I don't necessarily know why, but I think a lot of people feel that way. It's not a tangible moment where you're like, 'This is it'. It just is, somehow.''

The pair are still going strong, and Jessica can't wait to see her spouse take to the stage at the Super Bowl half-time show in February next year.

Speaking about the 36-year-old singer's performance, she said: ''It's going to be good. I guess I could be a little bit biased, but I think he puts on the best show of anybody. I'm just excited for him to have a really incredible place to perform and play some great stuff.''