Gwen Stefani says her boyfriend Blake Shelton's ''big heart'' and ''sense of humour'' are some of his ''sexiest'' qualities.

The 41-year-old singer/songwriter was named PEOPLE magazine's Sexiest Man Alive earlier this year and the 'Rich Girl' hitmaker admitted she feels ''totally responsible'' because Blake doesn't even like doing photo shoots.

Speaking on 'The Ellen Show', she said: ''I feel totally responsible because he's just so not that person.

''He doesn't even like to do a photo shoot, you can never convince him to do it.

''For me its just that big old heart, and that sense of humour. He doesn't even take himself seriously, and he's just such an incredible person. And that's sexy to me.''

Blake recently admitted he was going to ''milk'' his new title for everything because he has been ''fat and ugly'' his whole life.

He said: ''I mean, you can't be the sexiest man alive ... unless you're the sexiest man alive. I said this in the magazine when I did my interview for Sexiest Man Alive, that I had been fat and ugly my whole life, and if only for one year, I get to be sexy, I am going to milk this for everything that it's worth.''

What's more, the 'God Gave Me You' hitmaker joked he ''feels bad'' for his 48-year-old girlfriend Gwen because while she's dating a hunk, she now has to share him with the rest of the world.

He quipped: ''You know, I feel bad for her because she has been in the spotlight, and this symbol of beauty, and now this. You know what, it's going to be humbling for her but I think she's got a big enough heart. She can do it.''