Megan Fox, who has decided to do one movie a year, has said that it is hard to be a working mom.

In a recent interview with a parenting magazine, the 'Transformers' star asserted that she had to make one movie a year because she had to invest in her kids future and she had to be able to pay her kids' way through college and be able to provide for them, Contactmusic reported.

Fox married former 'Beverly Hills 90210' actor Brian Austin Green in 2010 and the couple have two children together, 2-year-old Noah and 4-month-old Bodhi.