According to The Sun, the pair have now confirmed their romance to family and friends, and she has told her bosses at celebrity agency James Grant Management.
A source told the paper: "They've adored each other for years and people have often thought they were together - but it's only recently they finally became an item.
They kept it quiet for ages but are at last coming to terms with being a couple in public." They are now thought to be on a romantic holiday, after a trip with Dec's TV partner Anthony Mc Partlin and his wife Lisa Armstrong.
It was an emotional night for Dec, who collected his first BAFTA TV award for Best Entertainment Programme without his sidekick, Ant.
He was joined by his colleagues, which included judges Amanda Holden and Alesha Dixon.
Declan Donnelly seems to have finally found love again, as it has been reported he is dating his long-term manager Ali Astall.
The 'Britain's Got Talent' host - one half of Ant & Dec - is said to have grown close to Ali after ten years of working together, and the couple have enjoyed months of secret dates.
ow.ly/k TZC30i R41c pic.twitter.com/cm0Zv IPz Iw A Golfer's Dream FANCOURT within close driving distance of SONAS ⛳️ #golf #golfer #golfcourse #links #pga #wgc #golfing #golfchat #golfdigest #golfholiday #golfvacation #golfresort #awardwinning #oudtshoorn #fancourt #george #southafrica #sa #golflover #golfersdream #sonas #1 pic.twitter.com/4xc Lfdp L5Q A gunman killed 35 people in Australia back in 1996. Massive reaction to our interview with Iranian Embassy Siege SAS hero Bob Curry on @GMB today.
Less than 2 weeks later, Australia enacted sweeping gun-control measures. Just outrageous that he is homeless while one of the terrorists from the Siege is living in a comfortable UK council home.
Speaking about his impending fatherhood, Dec admitted that he found the idea of becoming a dad very "exciting" whilst his wife and talent manager Ali, 40, said she wished she could fast forward to meeting their newborn.
"I just wish it would come out now, that we could fast-forward to having the baby.
It's the third time the group take home this award, having won it before in 2014, 20.
RELATED: Ali Astall shows off baby bump at BAFTAs with husband Declan Donnelly The star took to the stage to collect the award from Mo Farah and Claire Balding, but did not make an acceptance speech, leaving it to the producers.
Speaking about his relationship in a rare confession, Dec explained: “I think we’ve always been attracted to each other but it has always been that thing of we work together. Ali is part of James Grant Management, who take care of Marvin and Rochelle Humes and Holly Willoughby.