Lindsay Lohan has reportedly ''stumbled'' in her bid to stay sober.
The 'Mean Girls' actress - who underwent her sixth stint in rehab last summer - has been seen partying in London in recent weeks and though friends of the star admit she has drank alcohol recently, she is now back on the right track.
The source told RadarOnline.com: ''Lindsay was off the wagon, everyone has their stumbles, everyone will go out to drink.
''She fell off the horse but she picked herself back up and got back on. It's a struggle. Just because you have a hiccup doesn't mean you have to hold your breath.''
According to the friend, 27-year-old Lindsay is doing better than ever and working hard to feel good about herself.
The source added: ''Lindsay's in clubs but she's not drinking.
''Her friends have never seen her doing so well.
''Lindsay goes to the gym every single day. She's really trying to stay sober. And she's taking it one day at a time.''
Meanwhile, the 'Machete' star was noticeably absent from her brother Cody's graduation celebrations at the weekend. The 17-year-old student was joined by his mother Dina, grandmother, and siblings Dina, Ali and Michael Jr. in Long Island to mark the end of his schooldays, but his famous sister remained in London.