Lady Gaga has been helping her father with the opening of his restaurant.

The "Judas" hitmaker -- real name, Stafani Germanotta -- has been advising her dad Joe Germanotta on what to put on the menu at his New York eatery Joanna Trattoria, while sister Natali has been creating art to go on the walls.

A source told The Sun newspaper: "It's a real family effort. They've all been getting stuck in."

The restaurant's food selection includes a 10-layer lasagne, Grandma Rosie's meatballs, Nutella doughnuts and mini-martinis.

It will be run by Joe and celebrity chef Art Smith, and although Gaga has been happy to help out in the kitchen, her father sometimes worries because she is left handed.

He said: "She's left handed and every time I watch her chop, it makes me cringe."

While Gaga has been helping out in the restaurant, her parents have warned fans not to expect the eatery to be filled with memorabilia relating to their famous daughter.

Joe told the New York Times newspaper: "If they're expecting to come in here and see Grammys and pictures and stuff like that, it's not going to happen. [But] she generates a lot of sizzle."