Dallas's success with Leeds also saw him approached by Borussia Dortmund striker Erling Braut Haaland for his shirt after Northern Ireland's defeat by Norway earlier this month.
Haaland, 20, was born in the West Yorkshire city when his father Alf-Inge played for United.
"When we swapped shirts he just said 'Marching on Together'," Dallas said in reference to the club's anthem.
"Everyone thinks it is a bit strange he said that but it is because of the connection with Leeds with his father and he wants us to do well.
"He wished me all the best with Leeds and it came as a surprise he wanted to swap shirts with me."