A source said: “Steph and her girlfriend are absolutely thrilled.
“Everyone at the Beeb is delighted too — she is one of the most popular faces on and off the red sofa.
“But she won’t be doing any magazine shoots any time soon — she values her privacy too much.”
Today, in view of her 356,000 followers, she wrote: “I see my news is out! Yep, I am no longer with pot belly……I am now with child #babyonboard,”
Back in January last year, Steph was forced to deny rumours she is pregnant.
Taking to Twitter, she told her 356,000 followers she had a “pot belly” and was not carrying a child.
She tweeted: “For those who are congratulating me on my ‘pregnancy’. I am not ‘with child’, I am ‘with pot belly,’ followed by a pig emoji.
She later added: “I’d definitely be in the wrong job if I got offended by comments like that.
“Even my own auntie asked me once if I was pregnant after seeing me on the telly — that’s just life on camera.”
News of the presenter’s reported pregnancy comes just days after Steph left Carol Kirkwood red-faced after accusing her of flirting.
Carol appeared to be taken aback after Steph joked she had been “flirting” around Wimbledon.
The exchange began when Carol delivered the weather back on Thursday amid Wimbledon week.
The weather presenter then spoke to Rob Kennedy, a head chef.
She then asked him: “Could you rustle up a few pancakes for us while I do the weather? That would be very nice,” which left Steph giggling in the background.
“No problem at all,” the chef responded with a grin.
Carol then asked Steph and her co-host Charlie Stayt if they wished they were there.
Steph replied: “Aaah I certainly do it looks gorgeous.
I tell you what Carol, are you going to flirt your way round Wimbledon?
“You were hugging the florist earlier, now you’re asking the chef what time he finishes!”
Laughing Carol replied: “Steph you have got no shame!”
BBC Breakfast continues tomorrow from 6am on BBC One.