Justin Bieber's grandmother has given the 19-year-old some wise words of advice - pull up your trousers.

The singer is well known for wearing lowly-strung trousers and not everyone is fond of his underwear-flashing style.

One person in particular who isn't a fan of it all is his granny Diane Dale (pictured above left), who told E! at the premiere of Bieber's new film Believe:

"He should pick up his pants."

Her husband Bruce Dale, however, interjected: "I like it."

Speaking meanwhile about the tabloid press interest in Bieber's private life, Diane Dale said:

"I just ignore it. It's going to happen anyways. It doesn't matter who you are and a lot of it isn't even true. Some of it is, but life's got to go on. He's 19 and he's got a camera shoved in his face and lots of money. What do you want?" Watch Justin Bieber and Tyga's 'Wait For A Minute' video below: