The Shameless actress was hoping to offer the Baby singer a friendly welcome to the neighbourhood after learning he had moved in next door, but she quickly realised she won't be hanging out with the pop star anytime soon.

In an interview with U.S. DJ Sway on Tuesday (17Mar15), she said, "Justin Bieber just moved into the house next door to me. He's my new next door neighbour. I went over to kind of offer him a neighbourly hello, and I'm not going to do that again, because he has, like, a ton of bodyguards there, and they're really scary."

She didn't even get to exchange pleasantries with Bieber, who was pulling up to his house as she knocked on the door.

She added, "He didn't wave (to me), but I saw him. He pulled up in his Bentley and just went inside. He was actually rapping (Jay Z and Kanye West's N**gas In Paris) as he got out of the car.

"It was so surreal to me, that I was like, 'I'm not going to go ask for a cup of sugar over there'."

And when the DJ asked Rossum if she'd like to get invited to one of Bieber's upcoming house parties, the actress said, "I don't think he's going to invite me. I think I'm too old for his demo (demographic). I'm 28. I think he wants young girls. And I'm not single, but I don't think Bieber cares if a girl has a boyfriend. I don’t think that’s a pre-requisite for partying with Bieber."

Rossum's revelation comes as Bieber's former Calabasas, California neighbour, whose house he pelted with eggs, slapped the pop star with a lawsuit, claiming his bad boy antics caused him emotional distress.