Robert Pattinson and Kristen Stewart. Photo via Bang Showbiz

Londoner Robert Pattinson was apparently close to proposing marriage to girlfriend and Twilight co-star Kristen Stewart before reports of her liaison with film director Rupert Sanders.

Pattinson is said to have been due to ask for the 22-year-old brunette’s hand in marriage in the spring and had even bought a £5 million Los Angeles mansion for the couple’s future, the Sunday Mirror reports.

Since pictures of Stewart and her Snow White and the Huntsman director Sanders emerged, the pair have publically apologised.

Sanders is married to model and actress Liberty Ross - who played Stewart’s mother in Snow White and the Huntsman.

Pattinson, whose character in The Twilight Saga: Breaking Dawn - Part 1 married Stewart’s alter-ego onscreen last year, is reported to be “angry” with Stewart and the 26-year-old heart-throb has purportedly moved out of their LA home.

Unless they patch up any differences, there could be an awkward professional moment for Pattinson and Stewart later this year.

They are contractually obliged to be pictured side by side on the red carpet at the premiere of their final Twilight movie together, The Twilight Saga: Breaking Dawn - Part 2.