The 1948 film "The Luck of the Irish" has a Spanish doubloon from the Armada starring as a "lucky coin." While visiting Ireland, American newspaper reporter Tyrone Power is given the coin by a Leprechaun. The coin appears throughout the film while the Leprechaun encourages the romance between Tyrone and Anne Baxter, an Irish girl who he met there.

An Irish travel poster then appears:

The poster reads: IRELAND Land of Romance Blarney Castle Co. Cork GREAT SOUTHERN RYS (IRELAND) (Railways)

Newspaper reporter Stephen Fitzgerald and another reporter Bill are driving in a remote part of Ireland. They manage to wreck the car and Stephen goes for help. Near a waterfall he meets a little man.

Stephen sees a little man and asks him for directions.

The little man gives him directions to a nearby inn.

The inn is run by the innkeeper Tatie and a young woman named Nora. Stephen tells Tatie about his experience, Tatie replies that Stephen saw the local Leprechaun, but Nora doesn't believe in these things. Tatie tells Stephen about the Leprechaun and how to capture the traditional "pot of gold." One has to spit on the gold or it will change into pebbles. Later Stephen watches the innkeeper put a bottle of whiskey outside, sees the little man take it, and follows him to the waterfall. Stephen jumps the Leprechaun, and after a brief wrestling, forces him to dig up his pot of gold.

The pot is full of gold coins.

The design of the prop coins appear to be based on a medieval Spanish coin design. Stephen tells the Leprechaun that he doesn't want the gold which surprises the Leprechaun. The Leprechaun takes a liking to Stephen and gives him a gold coin for "luck."

The coin is a film prop coin imitation based on an old Spanish coin of King Ferdinand. The coin legend reads "NAVARR" and "FERNANDVS." Stephen heads back to the inn, and by now he and Nora have become friends. She doesn't believe his story about the Leprechaun and he shows her the coin.

She tells him that it is a Spanish doubloon.

The Spanish Armada was a fleet of ships sent to invade England in 1588, it failed, and bad weather forced some of the ships to wreck on the coasts of Ireland. Stephen has to leave to go back to New York City and Nora sees him off. Stephen is engaged to Frances Augur, whose father is a wealthy and powerful newspaper publisher. Mr. Augur plans to run for the US Senate and have Stephen work for him as a press agent.

Stephen and Frances head out to a restaurant for a dinner date.

Frances has arranged for a furnished apartment for Stephen, and has designed it herself, with various pieces of avant-garde art. She has also hired a butler for him and the butler who shows up looks familiar. The butler introduces himself as Horace.

Stephen knows he has met Horace before.

Horace agrees that they have met before at a residence where Horace was a servant. Stephen has to take a subway to an appointment and he meets another familiar face.

Nora tells Stephen that she is in New York to handle some business involving her relatives.

Nora takes Stephen to an Irish pub.

Horace has been advising Stephen not to be a "servant" like him by working for Mr. Augur. Mr. Augur has become more demanding of Stephen's time, ordering him to work nights. Stephen runs into Bill, the reporter he was with in Ireland, Bill doesn't like the change in Stephen's personality brought on by money. Stephen tells Nora goodbye as he is going to marry Frances and work for Mr. Augur. He pulls out his "lucky coin" and discovers that it has turned into a pebble. He asks Horace what is going on.

Horace admits that he is the Leprechaun and that he came to New York to help Stephen, by bringing him gold (presumably meaning Nora). Stephen heads for a news conference where Mr. Augur is to announce Stephen's new appointment as manager of his newspapers. Stephen is having second thoughts and starts seeing things.

Stephen announces that he is resigning and plans to "sit next to a waterfall." Frances breaks up with him.

Stephen is now the one to leave a bottle outside.

Tyrone Power as Stephen Fitzgerald
Anne Baxter as Nora
Cecil Kellaway as the Leprechaun (Horace)
Lee J. Cobb as David C. Augur
Jayne Meadows as Frances Augur
Director: Henry Koster
Writers: Philip Dunne, Constance Jones, Guy Jones