Jason Manford quit The One Show last night following allegations that he shared sexual internet messages with female fans.
The 29-year-old comedian handed his resignation notice to bosses on the flagship show last night, just four months after taking the coveted presenting role.
He said in a statement: "I have decided after careful consideration to step down from The One Show to concentrate on my family and tour commitments."
Last night the BBC said: "We have got nothing to say except that we accept Jason's decision."
Speaking to The Sun, Manford admitted he had "flirted" with 10 or 12 people online which "went over the line with a few".
He also said he had talked to girls on Skype - a live online video link - while on tour.
The comic told the newspaper: "There were 10 or 12 people flirting and then with a few it went over the line.
"We would start off flirty, then innuendo and then a bit saucy. They were moments I thought 'I shouldn't be saying that'.
"I went on Skype with a few girls. They also sent pictures on Twitter. It all happened on tour.
"It was just nice to have some interaction I suppose. But the next morning I would wake up and think 'F***. Oh my God'."
The 7pm BBC1 flagship show is not due to be screened tonight because of the Children in Need charity telethon - for which Manford had pre-recorded material - and the next show he was due to present is on Monday.
However, his resignation is believed to come into effect immediately and he is not expected to present the show again.
Manford said: "I don't drink, I don't do drugs, so it's not like I've got those to blame. I have my own stupidity to blame. I've never felt so low."
Referring to his wife Catherine, he added: "We have had a serious sit-down about it and agreed that what we've got is worth fighting for. She's fine and we're fine."
He said he felt he had let his family down and, after showing his wife the Twitter messages, she was "disappointed".
BBC bosses are expected to hold talks over the coming days to discuss the situation and find a replacement to co-host the show alongside Welsh presenter Alex Jones.
Chris Evans has been hosting the show every Friday night to allow Manford to honour commitments on his UK stand-up tour.
Manford, from Salford in Lancashire, apologised to fans and his family at the beginning of the month after he was accused of exchanging a series of Twitter messages with a female fan.
It was alleged that he shared private messages with Debra McNamee, 22, after she contacted him through the social networking site.
According to reports, the presenter received two pictures of Ms McNamee, including a close-up of herself wearing a lacy bra.
Following the allegations, the father-of-two issued an apology which said: "I can see now that what started out as a bit of messing about and having a laugh on Twitter has been misjudged and I'd like to apologise to anyone that this has offended as that was the last thing I ever intended to do."
It was said that Manford, whose wife is expecting their third child, was first contacted by Ms McNamee on October 22. A day later it said he sent her a private message and asked her to send him a photo.
His last message to Ms McNamee was allegedly on October 30 - hours after a gig in Bradford, West Yorkshire.
Manford, who married his actress wife in 2007 and has twin one-year-old daughters, took over presenting The One Show from Adrian Chiles in July. He is an avid user of Twitter and has more than 200,000 followers. However, he has now vowed to stop using his account.
The comic, who last presented The One Show on Wednesday night, is due to play two sold-out shows at Newcastle City Hall tonight and tomorrow.
Meanwhile, fans posted comments on his decision to leave the show on Twitter.
Fiona2608 tweeted: "I know jason manford is in the wrong, majorly. But he always seemed like such a nice guy. Makes it even more sad really."
And tonyrudak said: "I suspect he's gone back to doing what he does best. A TV presenter he isn't!"