The 32-year-old singer - who is one quarter of the British boy band alongside Duncan James, Lee Ryan and Simon Webbe - popped the question to his girlfriend Rosanna Jasmin today (23.12.13), which is also her birthday, while on a romantic getaway to Paris, France.
A statement on Blue's official Facebook page reads: ''It is with great pleasure we are pleased to announce the engagement of Antony Costa and his beautiful girlfriend Rosanna. Antony surprised Rosanna on her birthday today with a visit to Paris where he asked for her hand in marriage and she happily said yes.
''Everyone in Blue and the entire management team wish both Rosanna and Antony the very best for the future and we are all looking forward to the wedding.''
Rosanna gushed about the news on her Twitter page, sharing a snap of her and Antony under the Eiffel Tower.
She captioned the picture writing: ''We're Engaged!!!!!!!!! (sic)''
Antony also thanked fans of the 'One Love' group for their influx of congratulations.
He tweeted: ''Thankyou for your lovely messages myself and @RosannaJasmin are so happy to announce our engagement!!! Bring on 2014 xxx (sic)''
Many ticket-holders couldn't get into the O2 Arena show on Tuesday night (September 19th) because they didn't bring photo ID to match their booking.
An album re-release, a new song and a documentary mark the singer's legacy this year.
The actor plays the titular hero in the forthcoming adaptation.