And while some of the comments were funny and sarcastic, few of them were kind.
The comedian quipped: “Bad day: Spent it on a 787 Dreamliner with Lance Armstrong and Manti Te’o’s ex-girlfriend.”
Fellow funnyman Seth Meyers was more scathing, writing: “Say what you will, he’s still the Lance Armstrong of d**kheads.”
The Voice host Carson Daly said: “I’m embarrassed that I was such a fan for so long.”
Meanwhile CNN host Piers Morgan said: “The fact @lancearmstrong admits he had to look up what the word ‘cheat’ means says all you need to know about the man. #LiveWrong.”
In a scathing attack he also wrote: “What a sniveling, lying, cheating little wretch @lancearmstrong revealed himself to be tonight. I hope he now just disappears.”
At least one celeb came out in support of the Livestrong founder though. Jack Osbourne wrote: “Honestly I don’t care that Lance doped. He gave people hope and that’s more important than anything.
“So what if he lied. #livestrong.”