They tied the knot in September after just one year of dating.
The Stranger Things actor, 45, also amused her daughters, Marnie, seven, and Ethel, nine, with his bizarre beatboxing skills.
‘Normal’: David Harbour entertained his wife Lily Allen at their London home on Saturday, by singing the Christmas classic, Silent Night, before making bizarre beatboxing noises
In a video uploaded to the Instagram Story of the singer, 35, David belted out the Christmas choir song while encouraging Lily’s youngest daughter to sing along.
Marnie looked noticeably bewildered yet entertained as he exercised his impressive baritone range.
She chuckled before responding: ‘Shut up David, shut up David, shut up David.’
Lily then joined in with David as she sung the lyrics: ‘All is calm,’ before her unassuming partner realised she had been secretly filming him.
Curious: The Stranger Things actor, 45, also amused her daughters, Marnie, seven, and Ethel, nine, with the Christmas choir song while encouraging Lily’s youngest daughter to sing along
‘Oh no,’ he quipped. ‘You’re not videoing this? Turn it off.’ His wife promptly zoomed in on his face while her oldest daughter giggled off camera.
‘Surveillance capitalism!’ he declared before resuming his carol singing.
‘Sing it Marnie!’ David said to the 7-year-old sat next to him.
Marnie appeared occupied with a Christmas gift and answered: ‘Now shut up, [but] that was a very good song.’
‘Thank you,’ he replied before he began humming a pop song. David subsequently mimicked bass noises with his impromptu beatboxing style.
Don’t hold back: Lily and her daughter Ethal were in hysterics as he continued to make strange noises while jiggling on their sofa
Lily and Ethal laughed in hysterics once more as he made strange noises while jiggling on their sofa.
David and Lily exchanged vows at the iconic Graceland Chapel in Las Vegas back in September, following months of secret planning.
And The Stranger Things star shared gushing words about his relationship with the ‘beautiful, incredible’ British singer earlier this month, branding her a ‘deeply kind individual’.
David also admitted that life with Lily and her daughters has made him feel ‘like more of a man’.
‘I married a beautiful, incredible woman who I love,’ he told People. ‘I have never met someone who is so deeply kind as her. I’ve never felt so taken care of and cared for by another human being. She really is just a deeply kind individual and I love that about her.’
On becoming a stepdad to Lily’s daughters, who she shares with ex Sam Cooper, the New York native admitted their relationship has made him see life differently.
‘I’m in a relationship with three women who all have very different opinions of me at various times,’ he said, adding that it ‘just makes you feel a little bit more like a man, to be honest. I just feel a little bit more like an adult.’
He went on to admit that becoming a family man has changed his views on fatherhood, making him feel ‘every cliché from every sitcom you’ve ever heard’.
He continued: ‘It’s a cliché that we make fun of constantly in television and in books and I had always watched it with a grain of salt going, “Eh, whatever, it’s not the real deal.” And now I am in it. That sort of hits it on the head.’
Family man: The Stranger Things star recently admitted that life with Lily and her daughters has made him feel ‘like more of a man’ as he gushed over his ‘deeply kind’ wife