Daniel Radcliffe struggled to keep a straight face on the set of the forthcoming Harry Potter movie - because SIR Michael Gambon was determined to make him laugh during takes.
The 19 year old reprises his role as the boy wizard in Harry Potter and the Half-Blood Prince, which is due for release next month (Jul09), while Gambon plays his school mentor Albus Dumbledore.
The young star loved working with 68-year-old Gambon - but his constant joking around caused constant problems for Radcliffe.
He says, "All the scenes with Dumbledore were quite difficult, but they were great fun. (Gambon) is wonderful and I love him and he's one of the greatest actors I've ever worked with, but it is amazing because he will be actively trying to make you laugh right up until the point the director says, 'Action'."
And Radcliffe is praying their good rapport will come across on the big screen.
He adds, "I think I'll be vaguely happy with the scenes between myself and Michael. I think they'll be good. Because we got to like each other very much off screen, I'm hoping onscreen that'll come across."