The former Girls Aloud singer gave birth to a baby boy on Wednesday (22Mar17) and the couple confirmed the news in a brief statement issued on Saturday (25Mar17), on the eve of Mother's Day in the U.K.

Now Liam has taken to social media to express the couple's gratitude for all the congratulatory messages they've received online.

"Thank you to everyone for the love and supportive messages for myself and @CherylOfficial," he wrote on Twitter on Monday (27Mar17). "It really means a lot."

The One Direction star's post emerged two days after he shared his joy at becoming a first-time father, revealing he and Cheryl have yet to settle on a name for the newborn.

"My close friends and family know there are very few times when I'm left speechless... wow!" he posted on Saturday, beside a Polaroid snap of Liam cradling his son. "I'm incredibly happy to welcome our new baby boy into the world, it's a moment that I will never forget for the rest of my life and my favourite memory I have so far."

Liam, 23, also openly gushed about his admiration for Cheryl, taking fans by surprise as the pair has tried to keep its romance private and didn't even confirm the pregnancy rumours until the 33-year-old could no longer hide her bump.

He continued, "I'm completely in awe of his incredible mother and how she has been the whole way through this, she's really made my dreams come true. We haven't named him yet but he's already capturing hearts including mine. I feel very blessed. Happy Mother's Day everyone!"

Cheryl also celebrated her new role as a first-time mum in a sweet message on Instagram over the weekend.

"On Wednesday 22nd March Liam and I became parents to an incredibly beautiful, healthy baby boy, weighing 7lb 9 and looking like a dream," she told fans. "Although he still doesn't have a name he is already stealing hearts. We are all madly in love and overwhelmingly happy with our little arrival. Happy Mother's Day to all the mothers around the world. A day that now has a different meaning to me forever."