Mariah Carey has told Beyoncé that having twins is the ''most incredible experience ever''.

The 'Hero' hitmaker - who has five-year-old Moroccan and Monroe with ex-husband Nick Cannon - has sent her congratulations to her 'Formation' singer friend after the 35-year-old star revealed she and husband Jay Z are expecting two babies.

Commenting on Beyonce's Instagram announcement that she's pregnant with twins, Mariah wrote: ''Congrats Bey and Jay!!! I'm so happy for you both.

''Having twins is the most incredible experience ever! Love, Mariah and the twins.''

In December, the 'Fantasy' hitmaker revealed Beyonce had attended one of her 'All I Want for Christmas is You' concerts in New York.

She shared a picture of them both backstage and wrote: ''I love you @beyonce thank you sooooo much for coming out tonight!(sic)''

And last year, Mariah admitted she would love to record a song with the 'Crazy in Love' hitmaker.

She said: ''I love Beyoncé. She knows this, most people know that. I'm a fan, I love her, and we have fun together, like, she's a fun person, she's really cool. I would love to do a collaboration with her.''

Meanwhile, Beyoncé - who already has five-year-old daughter Blue Ivy with her rapper husband - has smashed Instagram's record for the most-liked post with her first pregnancy picture.

Selena Gomez previously had the most popular post, with a photo of her of her drinking a can of Coca Cola attracting 6,315,187 likes.

At the time of writing, after just a day online, 8,490,004 Instagram users had liked Beyoncé's image and over 492,000 people had commented on the picture.