Tina Knowles made a huge error after she inadvertently revealed her daughter Beyoncé's real age - celebrating the star's 39th birthday - but Bey is only 38!

Now fans think that Bey may have been using an industry age - which some artists do to increase their longevity in the industry.

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She later edited the original post to include the time she was pregnant with Bey:

"38 years ago today you came into my life and I know without a shred of doubt that God sent you!!!" Tina captioned a picture alongside daughter Bey. 

"I had recently lost my mom and never thought that I could feel that particular kind of love again but 7 months later I was pregnant with you (39 years ago people). The moment I saw you I knew that that was IT !!!! We've been the best of friends since then. You have brought me such Joy and pride and love and friendship!!! Your heart is as big as Texas!! You are one of the best moms ever! And I love you soo much. Have the best birthday EVER!!!! Mom."

How old is Beyonce really?