A pregnant teenage waitress got an unexpectedly large tip when a sympathetic stranger left her US$1,000 in cash, according to a media report Friday.

After a lunch of burgers, fries and drinks with a bill of US$26.35, the woman left Amanda Newkirk ten US$100 bills and a handwritten note reading "Keep the change! Have a great day," the Roanoke Times reported.

The 19-year-old thought it had to be a joke. But the manager at the Ruby Tuesday restaurant confirmed the authenticity of the bills with a counterfeit-detection pen, according to the paper.

Erin Dogan, a 28-year-old widow, called Newkirk's general manager and said she had left the tip while at lunch with her fiance.

"It involved a lot more than good service at a great restaurant," Dogan told the Times. "I didn't need it. It helped someone who ... needed it. God put us there together. God answered my questions."

Dogan, whose husband died last year, told the paper she loves to shop and could easily have spent the money at a nearby mall. But she decided to put it to better use.

"It made me feel phenomenal," Dogan said. "It has changed my life."

Newkirk plans to use some of the money to help pay for medical bills related to her pregnancy. But aside from a few national radio and television appearances, life continues as normal for the teen.

"I'm not going to retire with a thousand dollars," she said with a laugh.