Ant - one half of Geordie duo Ant and Dec - was pictured arriving at Riverside Studios on Monday (17 February) to record the Celebrity Juice: Saturday Night Takeaway Special, to air on screens this week.
Ant suffered the incident after preparing a Sunday roast for his sidekick Dec over the weekend.
"God, it was painful," Ant told The Sun. "It hurt like hell. There was a lot of blood."
Ant was taken to hospital and was hoping to get the tip stitched back on, but medics were only able to clean and dress the injury, it was reported.
Ant, who was sporting a white bandage and two medical plaster strips around his thumb, seemed to be in good spirits despite the injury and still managed to sign photographs for fans outside.
Seeing the funny side of things, Dec even replied to a Twitter user today, saying: "It was a good roast tho! D."
Ant and Dec filmed the special alongside Dancing On Ice judge Ashley Roberts, I'm a Celebrity...Get Me Out of Here Now! comedian Rob Beckett, head panellists Holly Willoughby and Fearne Cotton and host Keith Lemon.
After filming the episode, Dec said: "Recorded a Celeb Juice @itvtakeaway special last night, still slightly traumatised!"
Last month Ant and Dec were awarded the Landmark Award at the National Television Awards to celebrate 25 years in television.
The boys will be back on our TV screens soon to host the new series of Britain's Got Talent, with judges Simon Cowell, Amanda Holden, David Walliams and Alesha Dixon. They'll also be returning with Saturday Night Takeaway this Saturday (22 February)
Celebrity Juice airs Thursday 20 February at 10pm on ITV2.
Watch the trailer for the Celebrity Juice special below: