The Oasis Dream colt ran on strongly under Jamie Spencer to take the laurels in the Japan Racing Association Vintage Stakes at Goodwood last month.
That half-length victory was a third on the spin, following a third-placed effort on debut at Newbury in May.
He received general quotes of 25-1 for next season's colts' Classic after his success at the South Downs track. The last horse to successfully land the Vintage-Guineas double was Galileo Gold in 2015.
Fellowes is now looking to step the Sheikh Ahmed Al Maktoum-owned Marbaan up in class following his Group Two success over seven furlongs.
Though he holds entries in the Champagne Stakes at Doncaster, National Stakes at the Curragh and Royal Lodge at Newmarket, his handler is eyeing the seven-furlong Lagardere at ParisLongchamp on October 2.
Last year's renewal was won by the Ralph Beckett-trained Angel Bleu, who similarly won the Vintage Stakes.
Fellowes said: "Marbaan seems really well and had an easy time since Goodwood.
"He is a such a sensible, straightforward character and he has taken that really well.
"We are just starting to increase his work again. He is in the Champagne, but I would say that is unlikely.
"We are probably not going to run at all that weekend, and I think we will probably head straight to the Lagardere. That is what I have got in my head at the moment.
"He is a Group Two winner, so if we go to the Champagne, we have to go against Group One opposition, carrying a penalty, which is never easy.
"He has already had four runs this year, so there is no need to go back to rush back.
"We could go to the National Stakes in Ireland, but I'm not sure I fancy taking on Little Big Bear on his home turf - I think I'll leave that.
"He has had four runs. Last year's Lagardere winner also won the Vintage and didn't run between the two and I don't see any need to (run again in between).
"At the moment, and I have to confirm this with Sheikh Ahmed, the plan is to probably head to France on Arc weekend."
Fellowes is also likely to rule Vadream out of the Haydock Sprint Cup next weekend, as he has declared her for the Listed Jenningsbet Hopeful Stakes at Newmarket on Saturday.
Last season's winner of the Group Three Bengough Stakes, the Brazen Beau four-year-old returned to Ascot and signed off her campaign with a three-length beating by Creative Force in the Group One British Champions Sprint.
Fellowes added: "The monsoon rain that hit Newmarket on Thursday morning, which came out of nowhere, means she has been declared to run at Newmarket on Saturday.
"She has got a bit to prove as she has had a couple of disappointing runs this year, but all of her form last year was on soft ground and I'm hoping a return to soft ground will see her return to best effect.
"Her work has been good at home and she seems happy, so we'll see. Hopefully that will tee her up for a big autumn.
"The Hopeful Stakes looks a decent race but not against opposition who, on last year's form, she wouldn't have any problems dispensing with. If she is back to form, you would like to think she will be thereabouts."