She styled her long bob in loose waves while opting for a soft make-up look.
It comes after Mollie's Radio 1 co-host Matt Edmondson grilled Little Mix's Perrie Edwards over the band's BRIT award acceptance speech last month.
Walk this way: The former Saturdays singer, 33, entered the building in central London in her chic outfit ahead of her Radio 1 show
Little Mix made history during The BRITs in May when they became the first girl band to win the title of best British Group after being nominated three previous times.
During their speech, Jade Thirlwall said: 'This award isn't just for us, it's for Spice Girls, Sugababes, All Saints, Girls Aloud, all the incredible girls bands we love you.'