The reality star got the letter 'G' inked on the lower part of his biceps and model Grace returned the favour by getting the letter 'O' tattooed near the side of her waist.
Proudlock first shared the 'his and hers' tattoos in a photo posted to Instagram on Tuesday (13 August). But it could have been a spur-of-the-moment act after he confessed: "@gracemcgovern What did we just do!! #tatt #oops #og."
Although they quickly adjusted to their new body art and happily flaunted it for photographers as they supported Andy Jordan's music debut at London's Voodoo Vaults Embassy last night.
Proudlock, who stood out from the crowd in orange neon specs, spent most of the night by Grace's side and the couple looked very affectionate as they watched the music showcase.
Proudlock and Grace seem to be going from strength to strength, and enjoying plenty of quality time together.
Last week, the Serge DeNimes fashion designer told his Twitter followers that he was having a chilled out evening with his girlfriend. He said: "Big Sunday night with my baby @gracemcgovern #mask."
It's not known how long the couple have been going out for, but last month, Proudlock kissed the brunette and shared an intimate photo of the pair on Instagram, sparking speculation that she was the new love in his life.
Proudlock hasn't had the best of luck on MIC after a short-lived romance with former co-star Sophia Sassoon last year, and his blossoming friendship and possible romance with Phoebe-Lettice Thompson quickly fizzled out too.
But we're glad to see Proudlock so happy. We wonder if Grace will make an appearance in the sixth series of MIC which returns later this year?!