As EW notes, Charlize Theron was cast initially but the writers' strike meant she had to jump ship to appear in Trapped, which was ready to go, instead. Thankfully, it gave Tennant an opportunity to take another pass at the script, alongside Cox and, funnily enough, "we turned it in the weekend Legally Blonde came out." As a result, the following Monday, they approached Witherspoon, whom Tennant had worked with in a TV movie a decade prior, to play Melanie. Although Witherspoon agreed, the specter of 9/11 loomed large and the production was concerned about being shut down. 

Thankfully, New York City was opened back up for business just in time. As Tennant sees it, the timing was surprisingly perfect. "We thought of our movie as such a nice tonic. It's a nice movie, it doesn't hurt anybody, and people needed to get back to work," he opined. Everybody was thrilled to be back working under the circumstances too. The rest is rom-com history. Outside of Theron's casting, Sweet Home Alabama had an alternate ending too, which was included on the DVD release. As Film Stories reveals, a joke about Melanie being dead was originally included but, luckily, test audiences nixed it.