Joe Jonas is ''smitten'' with his girlfriend Sophie Turner, because she doesn't let him pay when they go on dates.

The 27-year-old singer has been reportedly dating the 'Game of Thrones' actress for the past month, and sources now say he is quickly falling head over heels for her because she ''has her own money'' and isn't using him to get free dates.

A source said: ''[Joe is] smitten [because Sophie] has her own money.

''He loves her because she won't let him pay for her all the time, which is so rare in girls he meets. She insists on paying her own way for flights when he asks her to come see him and offers to pay.

''Plus, he thinks she's so smart and sexy.''

And despite having only been together for a short period of time, the 'Cake by the Ocean' hitmaker already believes the beauty is something special.

The source added to New York Post newspaper's Page Six column: ''He's telling friends there's something different with her, and he knew it as soon as they met.''

The former Jonas Brothers member and the 'X-Men: Apocalypse' star reportedly made their relationship official last month when they spent the Thanksgiving holiday season together, after having been romantically linked earlier in November when they were spotted cuddling up at the MTV Europe Music Awards.

A source said at the time: ''Sophie and Joe met through mutual friends. They have been dating for a couple of months. They spent Thanksgiving together in Mammoth Lake. They are really into each other and having a great time.''

Previously, the DNCE singer revealed he likes his dates to be ''low-key'', so he can ease the amount of ''pressure'' from both sides.

He said: ''I'd like it to be really low-key. I think there's this thing that happens where, with a first date, there's just this immense amount of pressure on both sides that it just has to be kind of magical.

''But the whole purpose is to get to know somebody, get a vibe going and then, from there, you kind of decide, 'Alright, do we want to do this again?' It's like the first course. A nice low-key dinner, maybe a drink afterwards, and then that's perfect.''