Friends of 20-year-old Macauley Campbell, known as Mac, have raised Â£14,000 for the cause in 24 hours.
David, who is from Southampton, said: "My heart goes out to Macauley's family. I sincerely hope I can be part of any tribute put together."
Candlelit vigils have been held at the site of the accident near Romsey.
The campaign to host MacFest in memory of Mr Campbell has been discussed using #MacFest.
Rob da Bank, who set up Bestival, has said he will support the event, as well as BBC Radio 1 and 1Xtra DJ Charlie Sloth.
Mr Campbell was driving a Volkswagen Lupo which collided with a BMW on the A3057 between Nursling and Romsey. He was pronounced dead the scene.
Fleur Gollogly, Mr Campbell's girlfriend, said they loved going to festivals together.
She said: "We were really looking forward to seeing Craig David in May.
"We thought we would tweet him and we never thought we would get the response we have had. It's unbelievable.
"To see the support makes it that little bit easier.
"Just like everyone else, I adored him.
"It does give me comfort to be at the flowers and be around his friends and family."
Flowers have been laid at the scene of the accident, as people visit for the vigils.
A family statement said he was "a truly loving and active young man in the prime of his life."
He worked as an apprentice fitter with Sparkes of Totton and he loved sport, especially rugby, his family said.
His brother Luke said: "The support from his friends has been amazing, just goes to show what a much-loved young lad he was."
Singer Craig David has said he will support an event set up in memory of a road crash victim after a social media campaign.