"Avengers" star Mark Ruffalo has a Twitter user to thank for doing the right thing.

A fan who goes by the Twitter handle of @ Trezeduet reached out to Ruffalo and tweeted, "Mark, I found your wallet in a cab in Chicago yesterday. DM me so i can get it back to you, thanks."

After waiting 24 hours for a response, the fan sent Ruffalo a followup message which read, "I have your wallet. Found it in a cab in chicago on Friday. Let me know the best way to get it back to you. Thanks."

Fortunately Ruffalo spotted the tweet on his popular feed and quickly reached out. "Can you DM me," he tweeted. "Just sent a DM," responded the fan.

The conversation was private, but we can only assume things went well because Ruffalo later tweeted, "You are a hero!"

Maybe he'll give him a role in the next "Avengers" film...