The 37-year-old former Spice Girls star has a daughter Scarlet, two, with her partner Thomas Starr.
Speaking to UK newspaper Daily Record about being a mum, she said: 'Motherhood is treating me really well and I am really enjoying it. It is the hardest thing, but the best thing.
'It's not without challenges, one has to be honest, but for me it has been fantastic. It feels like a new beginning and has affected me in a positive way.
'My priorities have changed. Scarlet is the most important thing in the world, but in work terms I have become more determined because I have got her.'