Britney Spears is ''really happy'' with her boyfriend Sam Asghari.

The 'Toxic' hitmaker has been romancing the hunk for over a year ever since he starred in her music video for 'Slumber Party', and sources have now said an engagement could be on the horizon as the pair are getting increasingly more serious about one another.

An insider said: ''[Britney] is really happy and I wouldn't be surprised if they got engaged.''

Sources also claim Sam is ''really good'' with the 36-year-old singer's two sons Sean, 12, and Jayden, 11, whom she has with her former husband Kevin Federline.

They added: ''Sam is really good with the boys and that makes Brit really happy. She cares a lot that the boys are comfortable with the person she's dating.''

If that wasn't enough, Sam is said to be ''understanding'' about Britney's hectic work schedule, and is supportive of her career choices.

Sources told Entertainment Tonight: ''Sam is also very understanding and flexible in regards to her work schedule, which is necessary. He genuinely loves and adores her.''

Britney first opened up about her romance with the hunk last January, where she recalled working with and getting to know him on her music video shoot.

She gushed: ''We were doing the scene where I was doing the walk scene through the hall to go through the door to go to the bedroom and we were sitting there and waiting and waiting together for, like, 20 minutes at a time. We were having to be literally stuck there together, so we were basically forced to talk to each other.''

Since then, the pair have gone from strength to strength, with Sam dubbing himself as the ''luckiest man on this planet'' during a birthday tribute to the blonde beauty in December.

He wrote on social media: ''HAPPY BIRTHDAY TO MY ONE AND ONLY,'' he wrote. ''Thank you for being you, thank you for showing me the true meaning of a beautiful woman and a strong mother, and most of all thank you for being mine. I consider myself the luckiest man on this planet @britneyspears #luckiestmanalive.(sic)''