Julia Roberts is celebrating her niece Emma Roberts' 31st birthday. The 54-year-old actress marked the occasion Thursday by posting a tribute to Emma Roberts on Instagram. Roberts shared a clip of herself and Emma Roberts wearing party hats and blowing on party horns as confetti flies in the air. "Happy Birthday Magical One! Oh how I love you. #waitforit," she captioned the post. Producer Rita Wilson, who is married to actor Tom Hanks, celebrated with the pair in the comments. "Happy happy day!!!!" Wilson wrote. Emma Roberts is the daughter of actor Eric Roberts, the older brother of Julia Roberts, and Kelly Cunningham. She has starred in several seasons of the FX series "American Horror Story" and also had a lead role in the Fox series "Scream Queens." Emma Roberts said in the March issue of Tatler magazine that she used to visit Roberts on the set of "Erin Brockovich" and "America's Sweethearts." "I'd write the wardrobe tags and organize the makeup brushes and watch how they did their continuity books," she said. "I would ask questions without a filter. This industry really is 'learn as you go.'" Emma Roberts expressed her admiration for Roberts but said she is making her own career in acting. "I never aspired to be her," she said of Roberts. "I love her so much, I love her work, but I'm just doing my own thing." Roberts will next star in the Starz Watergate drama "Gaslit," while Emma Roberts will star in the film About "Fate."