Mischa Barton Nip-Slip Wardrobe Malfunction 'Shocks' Martin Sheen [PHOTOS]: No-Bra Boob Flash After Suing 'Money Stealing' Momager Nuala Barton

Stunning actress Mischa Barton just sued her own "momager" Nuala Barton for breach of oral contract. But nevermind such legal issues - 29-year-old Barton's bare cleavage wants some extra media attention, too!

The former "OC" beauty recently attended an exclusive, star-studded Hollywood screening of the new historical-drama, Bhopal: A Prayer for Rain (Friday, April 10). Barton looked gorgeous while flaunting a casual black skirt and white blouse:

But she was NOT wearing a bra... And 74-year-old actor Martin Sheen definitely took notice!

Not only did Barton rock some epic side-boob throughout the entire evening, but at one point during the viewing her naked nipple was fully exposed - while sitting right next to Sheen!

And his shocked facial reaction is priceless - check out the viral snapshots at EOnline.com.

Pretty funny, right?

Sheen and Barton both star in the 2014 "disaster" flick (via IMDb):

Interwoven stories of people in India and US as they face dilemmas of life time in the months leading to the biggest Industrial disaster in human history that claimed 10,000 innocent lives within a few hours. Inspired by real events.

Barton looks rather content and relaxed considering she just filed a lawsuit against her mother for "fraudulent misrepresentation" amongst other causes of action. She is now seeking "recovery of what her own mother stole from her and to be able to proceed with her career free of the meddling that Nuala continues to engage and in damages she continues to cause" (via E! News). View the official court documents here. Neither party has yet to comment on the case.

But some fans care more about the naughty boob flash. This basically sums it up pretty well:

@brucexwayne: "HAHAHAHA WOW. and people used to rate this chick over Summer. WRONG WRONG WRONG." 

Apparently, Barton's back in the limelight with a bang!