Duke insisted that he do his own jump,
John Wayne's 9-year-old daughter really loved my show, and she wanted to meet me, ... So Duke got in his station wagon and drove down to the studio one day. That's how we met. ... He's the one who got me the part (in 'True Grit').
So John Wayne ... rolled in the saddle as his nag ran at a gallop in the snow toward the chest-high fence. The horse stretched, Duke rose, and the two cleared the fence with plenty of room.