'Con artist' actress Katherine Jenkins

Welsh opera singer Katherine Jenkins admits she felt like a ''con artist'' when she worked alongside Matt Smith and Michael Gambon in the 'Doctor Who' Christmas special.

Katherine Jenkins felt like a "con artist" when she filmed the 'Doctor Who' Christmas special.

The Welsh opera singer was shocked when she landed the role alongside actors Matt Smith - who plays the titular Timelord - and 'Harry Potter' star Michael Gambon, and feared bosses on the show would think she was "rubbish".

She exclusively told BANG Showbiz: "I got approached, and I thought it was something I would love to do, but I didn't know if I was really capable. So I went in to read for them, and I thought, 'If they think I'm rubbish, they just won't give it to me. Because they're not going to entrust an entire Christmas special on me if I'm rubbish, just so they don't hurt my feelings!' So I went in and read and I got the call on my 30th birthday to say I'd got it. It's been so much fun. Michael Gambon's in it - who plays Dumbledore in 'Harry Potter'. It's kind of one of those things where you think, 'How am I in this? He's an amazing actor, what am I doing working with him?' I feel like a con artist!"

Although she has already finished filming her top-secret episode in the sci-fi show - which will air in December - she admits she doesn't think of herself as an actress.

Speaking ahead of the launch of the Macmillan Cancer Support charity's World's Biggest Coffee Morning today (24.09.10), she explained: "I can't believe I'm going to be in 'Doctor Who'! I've filmed it already; we filmed in July and August, which is strange filming Christmas in the summer. It's brilliant! I don't think of myself as an actress and I haven't had any training.

"And I can't tell you if I sing in it. I literally can't say anything. I'm tightly bound by confidentiality agreements. I don't want to spoil it for everyone!"

Katherine recently became ambassador of the Macmillan Cancer Support charity, who she has worked closely with since her father passed away when she was 15.

For more information on today's fundraising coffee morning, please visit www.macmillan.org.uk/coffee