The Grenade singer was arrested in Las Vegas in September 2010 after being caught with the drug in the toilets of the Hard Rock Hotel and Casino.
However, he will have the case officially wiped from his criminal record after pleading guilty back in January 2011.
At the time, the judge presiding over the case ruled the 26-year-old star should pay a fine of $2,000, complete 200 hours of community service and undertake drug education classes.
However, Mars – who previously admitted he “did a foolish thing and has never used drugs before” the incident – has now exceeded the amount of required community service after logging more than 230 hours working for children’s and health-related charities, TMZ.com reports.
Blair Berk, the singer’s lawyer, will appear in court on his behalf today to see the charge officially dismissed.
After initially hearing the charges would be dismissed, the Just The Way You Are hitmaker – born Peter Hernandez – explained he was “appreciative” that he wouldn’t be convicted for possession.
Berk said at the time: “Bruno is very appreciative he is being given this opportunity as a first offender not to suffer any conviction and instead to have his charge dismissed. He is taking all of this quite seriously.”