DTM boss Gerhard Berger has revealed there was an attempt to get Valentino Rossi to join his fellow MotoGP star Andrea Dovizioso in racing at Misano next month.
The plan was part of a bid to increase the race's popularity, and Rossi was linked with a BMW guest drive.
Earlier this month, Audi announced that Ducati rider Dovizioso would take its guest driver slot at Misano, with both brands sitting under the Volkswagen Group umbrella.
It is unclear how involved BMW was in the DTM's attempt to get Rossi into the seat for Misano, but Autosport understands the Yamaha rider's contract prevents him from taking the opportunity.
When Autosport asked if the DTM had made an attempt to get Rossi a guest drive, Berger said: "To be honest, yes [we made an approach].
"My dream was having Valentino in the BMW and Dovizioso in Audi. I have a half-dream [now]!
He then joked: "[But] next year is coming..."
The DTM rounds at Brands Hatch and Misano are key to the series' on-going internationalisation aims, but both have struggled to lure strong crowds.
Last year, BMW ran Alex Zanardi as a guest driver at Misano, where the DTM trialled a night-race format that it ultimately did not retain for 2019.
"Misano also had potential to have this atmosphere [similar to the popularity at Zolder last weekend], but in Italy, if it's not MotoGP or Ferrari, it's difficult [to attract fans], said Berger.
BMW RBM boss Bart Mampaey explained to Autosport that a Rossi guest drive in the future would be "fantastic" but stressed he had not been aware of the attempt to get him into a seat for Misano.
When Rudolf Dittrich, head of BMW Motorsport's vehicle development, was asked by Autosport if BMW had been involved in the Rossi approach, he said: "For sure we are looking at an interesting guest driver line-up this year.
"Last year we had success with Alex Zanardi and we obviously want to continue along these lines.
"You talk to various people and see what calendar fits, the capabilities [of a driver] and if preferences fit. We are in talks with people, let's see what the season brings."
R-Motorsport Aston Martin team principal Florian Kamelger told Autosport that he was "open-minded" to running a guest driver in 2019.
This is despite the new-for-2019 squad having had a late build of its four Vantages and having to manage a limited supply of spare parts.
Kamelger would not confirm or deny if the team had prepared a fifth Vantage for a guest driver.