"Twilight" star Robert Pattinson is supposedly getting serious about marrying singer FKA twigs, his girlfriend of just a few months. But the British actor is taking thing one step at a time, E! Online reported.

Pattinson has yet to propose to Twigs, whose real name is Tahliah Debrett Barnett. But an engagement rock is still on hold. In December, the 28-year-old actor reportedly gave the Grammy nominee a promise ring, and Twigs "was ecstatic to get it," an unidentified source told the celebrity news Web site.

"Rumours of an imminent engagement continue to swirl," Britain's Daily Mail noted. The couple spent the holidays with Pattinson's family in England, and an unnamed insider told the newspaper that the actor's two elder sisters, Lizzy and Victoria, "adore" his new girlfriend and "totally approve" of their relationship.

Pattinson and Twigs had first been spotted together in September when they were out and about in Hollywood, People recalled. When the 27-year-old singer went on her European tour in October, Pattinson remained at her side, and the couple appeared to be very much in love attending Art Basel in Miami at the end of last year, the magazine added.

Last week, they were an item at the BRIT Awards in London, and the two appeared "inseparable" when they attended a party after the prize ceremony, according to the Daily Mail.

"[Pattinson] wants to marry [Twigs]," an unidentified male source told People. He said his friend was "much more calm and happy than before."

"[Pattinson and Twigs] are inseparable when they are together," the man said. "They live at his house," he detailed.

Another unnamed insider told E! Online that there was a "special connection between the two of them," describing one of their biggest shared passions.

"Music is a big part of the relationship," the source said, "because it means to much to them. They clicked instantly and they literally have been inseparable."

E! Online speculated that an engagement may come soon, possibly this summer when Twigs wraps up her tour and Pattinson completes a variety of projects that he has been working on.

Recently, Pattinson was asked about his former girlfriend's new alleged relationship. It has been widely reported that Kristen Stewart is dating her female best friend, Alicia Cargile, but he did not respond to the questions.