James Righton Acts Like "Lovestruck Puppy" Around Fiancee Keira Knightley

Keira Knightley and James Righton are seen in Soho on July 1, 2012 in New York City. Credit: Alo Ceballos/FilmMagic

Sure, Keira Knightley was initially attracted to the bad-boy rocker behavior of James Righton, 28.

Then the actress, 27, learned she could bring out a softer side of the Klaxons keyboardist. "He can turn into this lovestruck puppy around her," a mutual pal tells Us Weekly of the couple, who announced their engagement in May.

The proposal was the result of a full-on campaign by his guy friends, says the pal, after they worried Knightley would slip away.

"Honestly, they're good for each other," says the confidant. "They love being engaged."

Prior to meeting Righton, Knightley dated actor Rupert Friend for more than five years; she confirmed the end of their relationship in December 2010.

The Anna Karenina star and the rocker's romance was first made public after they were photographed kissing in an East London park last April. According to reports, they were introduced by mutual pal Alexa Chung.