Just Stop Oil supporters Emily Brocklebank, 23, Xavier Gonzales-Trimmer, 21, and Louis McKechnie, 21, are accused of causing £2,200 of criminal damage to the painting’s frame.
Brocklebank, from Leeds, pleaded not guilty in person at Westminster Magistrates’ Court on Friday afternoon while McKechnie, who was produced in custody, entered the same plea.
Gonzales-Trimmer did not attend the hearing.
The court heard the value of the alleged damage is “disputed”.
Aneka Thirurajah, defending, said: “They don’t dispute presence but they do dispute involvement.”
Brocklebank was granted conditional bail not to attend the art gallery while McKechnie was returned to HMP Peterborough.
A one-day trial will take place at Westminster Magistrates’ Court on November 22.