The 23-year-old daughter of Sir Bob Geldof and Paula Yates announced she'd given birth to a baby boy on Twitter last night.
Confirming the arrival Peaches Geldof said: "Yes, its true- I'M A MUMMY!!!!"
Later she updated her profile to say: "My little boy is the most beautiful thing in this world. When he holds @tomfromscum's finger with his hand its the sweetest thing ever. X"
Fiance Thomas Cohen also gushed on the social networking site, tweeting: "im a dad he is the most perfect thing ever so proud of his beautiful mum @peaches_g and overcome with joy x"
The pair's publicist confirmed the baby news, saying: "Peaches and Thomas are delighted to announce the birth of their son Astala. Both were overjoyed at his arrival this week."
The baby's full name is reportedly Astala Dylan Willow Cohen-Geldof.
The loved-up couple revealed to Hello! magazine that the choice of name was influenced by Tom's heritage.
They said: "We found Astala in a baby name book - quite an obscure one. This is going to be a very stylish baby.
"I wanted a Jewish name because my fiance is a Jew and the name is the male version of Esther."
In an earlier interview with the mag, Peaches revealed she felt her late mother Paula Yates was watching over her after she discovered he was due on her birthday April 24.
Peaches and Tom announced their engagement last December. The TV presenter was previously married to American musician Max Drummey.