It was reported on Tuesday (21Feb17) that Howard has missed the opening night of his bandmate Gary Barlow's new musical The Girls in London on Monday night (20Feb17) because his wife Katie Halil had gone into labour.
And Howard took to Twitter on Wednesday (22Feb17) to confirm the news and reveal the baby's unusual name.
"Hello Dougie Bear Donald! He's here and he's beautiful!" he wrote. "He arrived yesterday morning and we are over the Pluto. X"
Dougie is Howard and Katie's second child after their son Bowie, who was born in January, 2016. The singer is also father to Grace, 17, from his relationship with Victoria Piddington, and Lola, 11, from his relationship with Marie-Christine Musswessels.
The 48-year-old, who married Katie in 2015, announced the pregnancy on Twitter in October (16), writing, "Guess what? Me and katie are happy to announce we will have our 2nd child in Feb. Yay! No more sleep for another 2 years!"
Howard had been scheduled to appear at the gala performance of The Girls, a stage adaptation of the 2003 film Calendar Girls at London's Phoenix Theatre to support Gary, who co-wrote the production with Tim Firth.
A source told The Sun newspaper Howard was upset to miss the show but he "needed to be on standby for the arrival of his fourth baby", adding: "He has always been a rock for his bandmates and Gary completely understood why he couldn't be there. Everyone is really excited for the birth - it is just a matter of time now."
Howard will be heading out on tour with Gary and bandmate Mark Owen on 5 May (17). The Wonderland Live 2017 tour kicks off in Birmingham, England.