Tom Felton (Draco Malfoy), Matthew Lewis (Neville Longbottom) and James & Oliver Phelps (Fred & George Weasley) are to attend an event in London, England, when the European Half-Blood Prince tour rolls into the city, on June 19th.

The tour, which features cotumes, props, a video game preview and a chance to be in Deathly Hallows, will be open in Leicester Square from June 18th - June 21st. Tickets can still be won here. The last two days, however, do not require tickets.

Source: HPANA