The proud dad shared his first photograph of the boys on Instagram on Wednesday
He wrote: “A gift from God. Welcome to the world my little boys.”
His celebrity friends were quick to offer their congratulations among the sea of comments.
“Awww beautiful! Congratulations you guys!!” Wrote former Emmerdale co-star Natalie Anderson, followed by two red heart emojis.
“Congrats mate!! Fantastic news!” Added racing driver Chris Buncombe.
While ex Strictly Come Dancing star Laila Rouass opted for simply three red heart emojis.
Fletcher – who played Andy Sugden in ITV soap Emmerdale from 1996 until 2016 – and Marsden got married in 2015 following a romantic beach proposal in Wales.
They originally met as children before reuniting around a decade ago.
The couple also share daughter Marnie, five, and son Milo, three.
They first confirmed that they were expecting twins in January.