Lady Gaga's two French bulldogs which were stolen at gunpoint in Hollywood have been safely returned, Los Angeles police said.

The safe return of Koji and Gustav came hours after the singer, who was filming a movie in Rome when her pets were taken on Wednesday night, issued a plea on social media for "an act of kindness" to bring them home.

LAPD spokesman Officer Mike Lopez said a woman, who authorities have not publicly identified, brought the dogs to a police station where they were later handed over to the musician's representatives.

"The woman's identity and the location the dogs were found will remain confidential due to the active criminal investigation and for her safety," LAPD said.

Officer Lopez said two men suspected of stealing the pets at gunpoint from dog walker, Ryan Fischer, remained at large.

In a message posted hours earlier on her Twitter and Instagram accounts, Lady Gaga said her "heart is sick" over the violent robbery and vowed to pay $500,000 for the dogs' safe return, including from anyone who had bought or found them.

"My beloved dogs Koji and Gustav were taken in Hollywood two nights ago," she wrote in the post, alongside photos of the dogs.

"I am praying my family will be whole again with an act of kindness." 

It was not immediately clear whether the woman who brought the dogs to the police yesterday will collect the reward.

Police said in a statement that Mr Fischer, 30, was walking three of Lady Gaga's bulldogs in a residential area in Hollywood on Wednesday night when a car pulled up alongside them and two men demanded he turn over the animals.

"I continue to love you Ryan Fischer, you risked your life to fight for our family. You're forever a hero," Lady Gaga said.

Two suspects had got out of a vehicle and demanded Mr Fischer hand over the pets at gunpoint. He was shot once in a struggle with the two men who fled with two of the dogs, police said.

A third dog, Miss Asia, ran away during the incident before returning to the wounded Mr Fischer, and was later recovered by law enforcement at the scene.