On Wednesday (13 October), Webb announced that he and partner Dianne Buswell would be leaving the dance competition series early due to his ill health.
The comic said that he had believed he was “fit enough” to compete on the show despite having had open-heart surgery two years ago, but quickly realised that he had “bitten off way more than I could chew for this stage in my recovery”.
Responding to the news on Wednesday night, Mitchell, who was in the Strictly audience watching Webb on Saturday (9 October), said that he was “sad” to see his comedy partner and Peep Show co-star leave the competition.
“They did some really brilliant dancing, I thought. Sorry there won’t be more,” he wrote.
“And to those asking if I’ll be stepping in to replace him: I’m afraid not. I prefer to dance like nobody’s watching. And I can only do that if nobody’s watching.”
Webb has previously said that his heart problem was exacerbated by his alcoholism, with a doctor saying he was “two days from death” before his operation.
He was advised to quit Strictly by his heart specialist for “the sake of my health”, suggesting that he had taken part in the show in an attempt to “impress” other heart patients.
“They will know that recovery doesn’t always go in a straight line, and I hope they’re not too disappointed that I ran into the limits of my resilience much sooner than I’d hoped,” Webb said.
Strictly Come Dancing continues Saturday 16 October at 7pm on BBC One.
If you or someone you know is suffering from alcohol addiction, you can confidentially call the national alcohol helpline Drinkline on 0300 123 1110 or visit the NHS website here for information about the programmes available to you.