Beyoncé Knowles 'makes sacrifices' to keep her marriage harmonious.

The 30-year-old songstress tied the knot with rapper Jay-Z in an intimate ceremony in 2008. The pair have a solid relationship amidst the fickleness of the entertainment world, which Beyoncé credits to continual compromise.

'It doesn't matter who you are, what you do, or where you are from, your marriage will only work if you both put effort into it and make sacrifices,' she explained in an interview with Closer magazine.

'Before you're married, you can be selfish because you have nobody to answer to, but when you're married you both find things you have to change. Marriage is great because, if it's managed in the right way, it will make you a more complete person. It forces you to change the things you need to change about yourself and that can only be a good thing.'

Beyoncé and Jay-Z are expecting their first baby in February next year. Beyoncé has received a lot of support form best friend Kelly Rowland, who she thinks will make a great mother herself some day.

'There's no doubt about that and she's going to make an awesome mother when the time is right,' she gushed.

'She's very good with kids and she'll be so great with her own.'