It happened in Las Vegas but didn't stay there.
A woman who was holidaying in the Nevada city lost her mobile phone, and is now the envy of women worldwide.
The woman, known as Austin, posted on Instagram on Monday night: "Bad news is I lost my phone two days ago. Good news is Cristiano Ronaldo found it. Better news is he took us to dinner last night."
The attractive young woman also posted photos of her posing with 30-year-old football superstar Ronaldo.
Other photos seen online show him with Austin and another blonde woman, likely Austin's friend.
Another photo showed one of the women kissing the Real Madrid player on the cheek.
The three-time Fifa World Player of the Year split from long-term Russian supermodel girlfriend Irina Shayk early this year.
He was said to be dating Lucia Villalon, a Spanish TV presenter, in January.