Lady Gaga surprised fans at a screening of 'A Star Is Born'.

Lady Gaga via A Star Is Born Instagram (c)

Lady Gaga via A Star Is Born Instagram (c)

The 32-year-old singer turned actress greeted shocked fans and made a moving speech during the unexpected appearance at a showing of her latest film in New York City, hosted by YouTube star Tyler Oakley.

During her speech, she said: "I love you so much. Thank you so, so much from the bottom of my heart for being here tonight.

"It would be a lie to not think each and every one of you who has supported me over the years, I would not be here without you.

"You are fighters. You are beautiful, and I love you."

Gaga also gave a special shoutout to her co-star and director Bradley Cooper, who plays her love interest Jackson Maine, as she said working with the 43-year-old star has "been one of the greatest honours of [her] life."

She said: "All you need is just for one person to believe. So, I have to say thank you to my incredible director, Bradley Cooper. This is the moment that Bradley gives the film over to you and to the world. I am so grateful, and I am so humbled that it is moving people and that's all that matters. So, this our gift to you. We love you.

"Working with Bradley Cooper has been one of the greatest honours of my life. He fought for me to play this role."

Host Tyler then asked the star how she hoped the film - which is a remake of two films of the same name from 1954, and 1976 starring Judy Garland and Barbra Streisand, respectively - would impact this generation.

Gaga replied: "Be who you are, fight to be who you are."

The film's official Instagram account posted a video of the appearance, where the 'American Horror Story' actress made her entrance to excited fans wearing a stunning floor-length red glittering gown with a thigh-high slit which the star paired with black leather thigh high boots and black shades.

'A Star Is Born' hit cinema screens on Thursday (04.10.18).