The actress later teased her Instagram viewers by holding hands on camera with her out of sight husband as she left BBC Broadcasting House in a taxi.
Speaking to BBC Radio 4’s Today programme, Hart said: “The reason I put this little love story of mine in it was mainly because at the beginning of the book, yeah, I’m alone. I’m bed bound by this illness.
“And waiting in the darkness in a confusing place gives you the chance to long for what you want to do. And I realised I didn’t want to be alone.”
She added: “I really recommend it, honestly, getting married in the midlife is a full injection of joy and fun. It’s the best.”
Mr Fairs, from Bristol, proposed on a walk around Kew Gardens in January, as the pair stood by a bridge overlooking the lake.
‘Burst out crying’
In her book, Hart recalled that she “simply burst out crying, apparently saying yes before he had finished the sentence”.
She added: “I didn’t think a traditional proposal would affect me so.
“But there was someone knowing all my ridiculousness and brokenness and still willing to bend down, look up and commit to loving me and standing by me for the rest of his life.”
Mr Fairs, who owns a company called The Building Consultancy, is said to have married Hart at St Peter and St Paul church in Hambledon, Hampshire, on July 6.
Hart started out performing on stage at the Edinburgh Fringe in the early 2000s before taking on the role of Miranda in her eponymous television sitcom, which ran from 2009 to 2015.
She has taken time away from acting as she recovers from Lyme disease – a bacterial infection that can transfer to humans via a tick bite.