Opera star Katherine Jenkins has revealed she is “thrilled and surprised” after accepting a proposal from her boyfriend Andrew Levitas.

The romance came to light only last month when Levitas joined her as she collected her OBE from Prince Charles at Buckingham Palace.

The news drew attention as it was believed Jenkins was still in a relationship with Prince Harry’s close friend Adam Bidwell, who is known as Bidders. In fact, she has been secretly dating Levitas since October, and on Thursday she announced the engagement on her Facebook page.

Friends of the 33-year-old mezzo-soprano say she accepted the proposal several days ago but waited before disclosing the news because she was concerned that her wider circle of friends would worry she was rushing into the marriage.

But those closest to the Welsh star know she has been “head over heels” in love with Levitas for more than six months after meeting him in New York.

Levitas, 36, is a professor at the prestigious New York University and is a distinguished artist and filmmaker. Later this year he will be releasing the film Lullaby, which he wrote and directed. It stars Amy Adams, Jennifer Hudson and former Downton Abbey actress Jessica Brown Findlay.

Friends say the couple plan to marry in 2015 and are likely to have the ceremony in Wales, where Jenkins’s family lives, followed by a small service in America, where Levitas was born. A source close to the couple said: “Katherine has been preparing the announcement for a while. She is very excited — she loves how artistic and intelligent Andrew is.

“He is considering moving to the UK for her.”

Another friend said: “She has definitely left her party ways behind her since meeting Andrew, and that means some of her socialite friends have been left feeling as if they have been discarded. This relationship is moving very fast — they are so in love. I wouldn’t be surprised if she is expecting by this time next year.”

Jenkins was previously engaged to former Blue Peter presenter Gethin Jones, who proposed in 2011. But the couple split later that year, and shortly afterwards the singer left the UK to pursue fame in America. She now spends much of her time in New York with Levitas.