The 27-year-old singer and her rumoured boyfriend are set to visit his mother Marianne Nelson in Nevada before they take in some tourist attractions in the US resort in August, which is known for its casinos and spectacular stage shows.
A source told The Sun newspaper: "Cheryl's only been to Vegas once before and didn't get to spend much time there so she's really looking forward to it.
"She has already made a list of things she wants to do and said she wants to just be a 'tourist' and do all the tacky things people do there.
"She wants to see some shows and have a flutter on the roulette."
Last month, it was reported that Derek went to Las Vegas - known as Sin City - with Cheryl's younger brother Garry Tweedy.
The lads became firm friends as they partied the night away at the Moon nightclub at Palms Hotel.
A pal said time: "They drove to Vegas through the desert and had a right laugh along the way.
"Derek's really become a brother-like figure to Garry. Cheryl's really happy they are getting on so well."