The 36-year-old 'Dark Knight' star, who is the mother of daughter Ramona, eight, and Gloria, two, with husband Peter Sarsgaard, said she sometimes 'falls off the wagon' by resuming her habit of smoking, reported Contactmusic.
"I don't smoke cigarettes officially but now and then I fall off the wagon. I can't keep it up at home. I can't smoke as a mother - it's too much sneaking around," Gyllenhaal said.
"I'm buying cigarettes and I'm like, 'what am I doing? pull it together!," she added.
The actress currently starring in the TV drama 'The Honourable Woman', is struggling to find time for herself and is forced to sacrifice her hobbies of reading and exercising to spend time with her family.