During the months that Lou Costello was stuck in bed recovering from rheumatic fever, Bud Abbott called often. “They played this game on the phone called ‘Guess the Blood Pressure,’” Lou’s daughter Chris Costello tells Closer. “He and Bud both loved to gamble — although they weren’t good gamblers. They lost a lot of money.”

For a time, they could afford it. During World War II, the comedy team of Abbott and Costello made Bud and Lou the highest-paid entertainers in the world. Their friendship, born out of a business partnership, would survive petty arguments, personal tragedies, trouble with the IRS and even death.

“They were together 21 years and had their disagreements,” says Chris, “but it never meant that they hated each other.”

Inside Lou Costello and Bud Abbott’s Friendship as Detailed by Lou’s Daughter Chris

One night in 1931, straight man Bud stepped in for Lou’s no-show partner at Brooklyn’s Casino Theater — and a new comedy team was formed. “Every comic on the circuit wanted the opportunity to work with Bud,” says Chris. “He’ll go down in history as one of the greatest straight men ever.”

He found a worthy partner in Lou, who played the good-natured nitwit with great physicality and a genius for ad-libbing. “They had tremendous chemistry, timing, and they could be spontaneous,” explains Jim Mulholland, author of The Abbott and Costello Book. In fact, the pair never performed their signature routine “Who’s on First?” the same way twice. “They reasoned that if they memorized the script, it would become stale,” explains Chris. “It just wouldn’t have that magic.”

Their act took them from burlesque stages to radio, Broadway and finally movies. Bud and Lou’s second film, 1941’s Buck Privates, made these two New Jersey-born performers superstars overnight. In 1943, Universal paid them nearly $800,000 — the equivalent of $13 million today.

Stardom brought bigger headaches. They squabbled over what projects to choose and billing — Lou became especially irate if anyone accidentally called him “Bud.” But Chris contends that the bickering never meant anything. “They had very different personalities,” she says. “But God help anyone who said anything derogatory about Bud around my dad. And the same with Bud towards dad.”

When it mattered, the men came through for each other. Bud suffered from epilepsy, and Lou stayed alert for signs of a seizure. “Costello would have to punch him in the stomach to bring him out of it,” says Abbott and Costello in Hollywood coauthor Ron Palumbo. Bud, meanwhile, gave his money and time to the Lou Costello Jr. Youth Foundation to help memorialize Lou’s son after the infant drowned in 1943. “They went on tour to raise money for the foundation,” Chris says.

Abbott and Costello split up in 1957, but Bud and Lou never lost touch. When Lou died after a heart attack in 1959 at age 52, a shattered Bud was a pallbearer.

Chris recalls visiting him at home. “We were sitting in the living room and Abbott and Costello came on,” she says. “Bud’s eyes filled with tears. He looked at me and said, ‘I just miss my buddy.’”