This ended O'Brien's brief theatrical career of about eight years;[90] and therewith departed from the stage the most powerful rival Woodward ever encountered upon it; the original actor of Young Clackit, in the "Guardian;" Lovel, in "High Life Below Stairs;" Lord Trinket, in the "Jealous Wife;" Beverley, in "All in the Wrong;" Colonel Tamper, in the "Deuce is in Him," &c. In one character O'Brien must have exhibited extraordinary humour--Sir Andrew Aguecheek. He was playing it on the 19th of October 1763, a period when it was the custom to have two sentinels posted on either side of the stage, and one of these fellows was so overcome by Sir Andrew's comicality, that he laughed till he fell, to the infinite amusement of all who witnessed the circumstance. O'Brien's marriage caused a sensation in the fashionable world, and brought sorrow to some parties. On April the 9th, 1764, Walpole writes to Mann:--"A melancholy affair has happened to Lord Ilchester; his eldest daughter, Lady Susan (Strangways), a very pleasing girl, though not handsome, married herself, two days ago, at Covent Garden Church, to O'Brien, a handsome young actor. Lord Ilchester doated on her, and was the most indulgent of fathers. 'Tis a cruel blow." Three days later, Walpole writes to Lord Hereford, "Poor Lady Susan O'Brien is in the most deplorable situation, for her Adonis is a Roman Catholic, and cannot be provided for out of his calling." Sir Francis Delaval, one of the rich amateur actors of his time, touched by her calamity, "made her a present of--what do you think?" asks Horace, "of a rich gold stuff! The delightful charity! O'Brien comforts himself, and says it will make a shining passage in his little history!" As O'Brien had not the means whereby to live without acting, his wife's noble family thought it would be no disgrace, to _hide_ the disgrace which had fallen upon it, by providing for the young couple--at the public expense. Accordingly, a grant of lands in America was procured for them, and thither they went. On Christmas Day 1764, Charles Fox writes of his cousin, to Sir George Macartney:--"We have heard from Lady Susan since her arrival at New York. I do not think they will make much of their lands, and I fear it will be impossible to get O'Brien a place." When Charles Fox wrote this he was about fifteen, and looked as handsome as he does in the famous picture at Holland House, which contains also the portraits of Lady Susan, who married the actor, and Lady Sarah Lennox (Bunbury), who did _not_ marry the king.