Robert Pattinson believes FKA twigs is "his greatest love."

Robert Pattinson and FKA twigs

Robert Pattinson and FKA twigs

The 28-year-old actor, who recently got engaged to the 'Two Weeks' hitmaker after seven months of dating, reportedly immediately knew he wanted to spend the rest of his life with her.

A source close to the 'Twilight Saga' star, who split from co-star Kristen Stewart in May 2013 after three years of dating, said: "They've been living together and he's been calling her his greatest love."

Friends close to the couple confirmed their engagement shortly after rapper T-Pain claimed the 27-year-old singer - whose real name is Tahliah Debrett Barnett - was too busy to collaborate with him in the recording studio as she is planning her wedding but later tried to pass his comments off as a joke.

The couple were thought to have exchanged promise rings in December.

But the insider told "I hear they were telling people they were promise rings, but I haven't seen Pattinson wearing one. They only told a few people about the engagement,"

The British heartthrob is planning to support his new fiancée at the Coachella Valley Music and Arts Festival in Indio, California later this month.

The source explained: "They've been inseparable. He's planning on going to Coachella to support her."