Sean - the son of late Beatles star John and his wife Yoko Ono - and partner Charlotte Kemp Muhl took to their social media pages on Tuesday
to announce the happy news, alongside a picture of themselves with the new addition.
Sean wrote on Instagram: "(Charlotte) and I have created a Human Bean. His name is Aurelius! Thank you!"
Meanwhile, model Charlotte also shared pictures on her Instagram page, as she wrote: "We made a human! Am convinced DNA is agentic alien quaternary code.
"The sleep deprivation only adds to the surrealism…Burping technique tips welcome."
In addition, Charlotte said she and Sean were already introducing Aurelius to music, playing him music by Russian composer Igor Stravinsky and techno star Aphex Twin.
Upon announcing the arrival of their baby boy, Sean and Charlotte were inundated with messages of congratulations from their famous friends and followers.
Among them, a message from Zak Starkey - the son of John's Beatles bandmate Ringo Starr - who wrote "Amazing!"
While Patti Smith commented: "Oh Sean I'm so happy for you both."
Lindsay Lohan wrote: "Congratulations to the beautiful couple!!"
Sean and Charlotte first met at the Coachella music festival in 2005, but the pair didn't start dating until 2007.
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