Jenna Coleman was a total brat

http://www.frockflicks.com/costume-designer-james-keast-frock-flicks-guide/

“We had a crowd AD and we would not even get a list of names on the day we were filming, and I would say – who are we fitting? So these people would turn up and we would have to try to fit them to the sizes of the costumes we had. We had to recreate the coronation or the opening of parliament without any information so I didn’t even know what I was trying to supply. So I did my research, I did what I thought was right. Then on the day I would get told, there are these six soldiers, you think what six solders? I said you cannot come to me and ask for this stuff when I didn’t know I was supposed to have it and I haven’t got it… They did that with principles as well – you would get the name the night before… They wouldn’t get a crowd AD that was any good so you were fire-fighting all the time. Dealing with last minute principle casting and extras that did not look right. It was a complete nightmare…

“We did the opening of parliament and I think I maybe just got away with that, but they will have to do some CGI, and then we were doing the coronation and suddenly this advisor appears who knew everything about everything and was pointing out to the set and art department everything that was wrong. So suddenly they were coming to me and saying we need four of these and four of these and another two bishops and I’m saying but I’ve only got what you asked me for yesterday – did you not know yesterday?– No we didn’t, it’s the advisor that’s telling us what we need to have. So you say to the director that you cannot shoot it that way because we do not have what’s needed because I was told we needed that that and that, and this this and this, and that’s what I’ve done. And then the advisor would get involved and start saying well, that’s the wrong uniform, he shouldn’t be dressed like that, he should be dressed like this and you are made to look a fool… When it actually came to thecoronation bit, she goes in to a room and she is disrobed and then she puts that thing on – they all have names – then she goes back and is crowned blah blah blah. Then she goes backstage takes the cloak off and puts another one on and walks out. I did all that because I’d done my research, and we had the cloak all made, the cloth of gold thing and it looked very good, but you think please don’t focus on anybody else because it looks terrible…

“I went and did a lot of research and in the Museum of London there is the actual dress that she wore as Queen the day after she was told her uncle had died. It was black but it’s all faded so much it has gone a reddy-brown colour. I made it in black silk moire and it looks very beautiful on camera – except on Day 1, the director decided to get her to lean against the wall and slide down the wall in a very modern fashion – but the wall had just been painted white so all down the back of her black frock is white paint…

“There was an actress who played the queen’s mother – who collected lace – so I made everything for this character from lace. Then the actress tells me just before filming, that she is allergic to lace – which is not the case – but she won’t wear it, unless you then spend the time with her to be with her as she dresses – in which case there is nothing wrong with the lace, but if you are running around between five other principles, then that’s when there is something wrong. For example, she can’t act properly because her petticoat is too heavy or something. And you explain, well actually that is because they used to wear a minimum of three petticoats and the problem was these petticoats were so heavy they could hardly move, so somebody came along and thought I’ll invent the crinoline, and that means you don’t have all that weight and that’s good. And she’s really interested in this, but then she still says ‘yeah but I can’t act in that because it’s too heavy – have you got a crinoline?’ And you have to say – no, because it is only 1846 and crinolines weren’t around until 1851–ish. And I’m thinking, ‘arrrrgggghhhhhhhh.’” (Costuming the everyday: Interview with James Keast)

It wasn't Jenna Coleman anyway, it was somebody else. OP was mistaken.