The baby was born Wednesday, and was given the middle name Nicholas in honor of two doctors who treated Boris Johnson while he suffered from coronavirus last month.
"Wilfred after Boris' grandfather, Lawrie after my grandfather, Nicholas after Dr Nick Price and Dr Nick Hart - the two doctors that saved Boris' life last month," Carrie Symonds said on her private Instagram account Saturday.
"Thank you so, so much to the incredible NHS maternity team at UCLH that looked after us so well. I couldn't be happier. My heart is full," she added.
Johnson returned to work on Monday, after becoming the first world leader to fall ill with coronavirus in March.
The UK Prime Minister spent three nights in intensive care in early April, before his condition improved.
Symonds previously said on Twitter that she had also experienced coronavirus symptoms.
The couple announced in February 2020 that they were engaged to be married.