The TV host left David Koch stunned with her on-air "surprise" - revealing she's expecting her first baby with husband Neil Varcoe.

Seb Costello has spoken out after being targeted by an “errant tweet” from Sunrise reporter Edwina Bartholomew.

The Channel 9 reporter confirmed on radio this morning that he would be discussing the situation with lawyers.

This comes after reports Nine is considering legal action over the extraordinary tweet posted by Bartholomew, claiming her words have had a “devastating” impact on one of their journalists.

The drama started on Thursday when Nine News Melbourne published a tweet featuring Costello, who filed a story outside the Victorian state parliament after a security scare.

A man had driven a vehicle containing flammable liquid to the front steps of the building and threatened to set himself on fire.

Bartholomew posted a reply to the tweet on Saturday morning, saying: “Surprisingly articulate for a (censored).” We can’t reveal the word she used for legal reasons.

Her tweet was deleted 50 minutes later.

Costello — who is also a newsreader for Triple M’s Hot Breakfast — addressed the story during Monday’s show.

“Look, it’s not ideal what was said. I spent the weekend with family and it’s not ideal with family either,” he began, before show host Eddie Maguire interrupted.

“And you’ll be spending today with lawyers?” he asked, prompting a cagey response from Costello.

“Well, and that’s probably why I can’t say too much, that was an accurate (Herald Sun newspaper) report, I’ll be talking to lawyers today and that’s all I’ve got to say. I’ll move on and do my job,” he told the hosts.

Meanwhile, Nine told news.com.au on Monday that Costello was “devastated and shocked” by the tweet.

“Seb and Nine are devastated and shocked at the damaging and false nature of this personal attack on a public platform,” a spokesperson said.

Bartholomew is currently in London on assignment for Sunrise.

“I was half asleep and on the other side of the world,” she said to the Herald Sun.

“My apologies to Seb and all involved. No offence was intended and hopefully none was taken.

“It was clearly a mistake and the errant tweet has been deleted.”

News.com.au has reached out to Channel 7 and Bartholomew for comment.

TV Blackbox reports Nine management has held discussions with its legal team to decide on a course of action.

Nine and Seven are not making public comments at this time.

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Bartholomew and her husband Neil Varcoe are expecting their first child. She announced her pregnancy on air in June.

Earlier this month, she spoke to the New Daily about the exhausting challenge of doing TV while pregnant, admitting it was “quite torturous”.

First, she told the publication she felt good, but a day later got in touch with the truth.

“After speaking yesterday, I returned home to have a nap on the couch for three hours and then went to bed at 8pm and still couldn’t get up to work at 5am,” she admitted.

“So please disregard my comments about feeling hunky dory. Turns out that’s bulls**t and I’m buggered. I think I probably just needed to admit that to myself.”

Bartholomew and Varcoe are also in the process of renovating their Sydney home.