THE "How to impress a bloke" classes at Hogwarts must have been pretty elementary, my dear Emma Watson.

If you want to impress a bloke, don`t move him in with your parents in the early days of the relationship.

The actress and her American boyfriend Johnny Simmons are living on the top floor of her dad`s North London gaff.

The Harry Potter star is shacked up with the actor in the posh attic rooms of the £2million home while he gets to know her family.

It`s not quite a bedroom under the stairs but it`s close.

A source said: "Things are getting pretty serious between Emma and Johnny so she wanted to take him back to London to meet her parents.

"They`ve been having a brilliant time together. Emma knows the city like the back of her hand so is a great person to show him around.

"They`ve done loads of tourist spots but she has also been taking him to a few flea markets and some great local pubs.

"They`ve been taking bikes or eco-cars to every tourist trap in the capital, including the London Eye, Big Ben and St Paul`s Cathedral."

Surely she has taken him to Platform Nine-And-Three-Quarters at King`s Cross Station?

But it might be a bit too early to take him up the Oxo Tower.