Sharing snaps on social media, the comedian joked: “Am I the most engaged , reliable godmother of all time?”
The 37-year-old welcomed Otto, her third child, with husband Spencer Matthews (34) on April 18.
The proud mum, who also has a son Theodore (4) and a daughter, Gigi (2) with the former Made in Chelsea star, said they had a “lovely day” celebrating the special occasion.
She also revealed that the designer christening gown Otto was wearing on the day was passed down from Theodore..
Posting a snap of her holding the seven-month-old at the mass, the Howth native explained: “Otto is wearing Ts old christening gown that Paul Costelloe made for him.”
Vogue’s close pal and My Therapist Ghosted Me podcast co-host Joanne McNally, who took on the role of godmother, also posed for pictures on the day.
Sharing snaps on social media, the comedian joked: “Am I the most engaged , reliable godmother of all time?
“No, but am I willing to change my ways for my tiny Victorian, famine baby godchild Otto? Dressed in blue leather trousers and a pink blazer, she added: “Also no .. (only kidding welcome to heaven baby Otto everyone loves you)”
Fans praised Joanne in her new role, with one person saying: “Lucky Otto, what a gorgeous boy. Everyone needs a Joanne Mcnally as their godmother”.
Another added: “Delighted .. he’s a very lucky boy to have you as Godmum x”.
While a third said: “His life will be full of magic with you as his godmother …. Little does he know !!!!”.
In July of this year Vogue spoke about her struggle with anxiety throughout her pregnancy with Otto.
Opening up about pre and post-natal depression, on Taboo Talk, with guests Luisa Zissman and Anna Williamson, she revealed her experience of the conditions.
“I feel like people are always scared about talking about it or going on medication when you actually really need it,” she began.
“I experienced really, really bad anxiety at the start of this pregnancy.
“Just life was happening and it was really stressful and they told me to come off, because I have my anxiety medication.”
“I don’t ever take it but I needed it then - and then I was like, ‘Right I have it here can I take it?'”
“And they were like, ‘You can’t take that’ and then after not taking it for three months that I would have needed it they were like, ‘Ah you can take the odd one’ and I’m like, ‘[Jesus].'”
She also opened up about the struggles she faced when sharing her pregnancy online, saying she received backlash for using formula.
“I always start with those little bottles in the hospital before your milk comes in,” she said.
“And I remember posting about my hospital bag and they were in the bag and people were contacting the ASI saying I was breaking advertising standards and I was like, ‘I didn’t get paid to put that in my bag.'”
The Dubliner recently revealed that she is open to having a fourth child after welcoming her third baby back in April.