The pair were Wednesday granted a wild card just a day after Murray, 37, pulled out of the singles due to his failure to regain full fitness following a back operation.
The two-time Wimbledon singles champion will also play men's doubles with his brother Jamie at the All England Club, launching their campaign on Centre Court on Thursday.
The mixed doubles event starts the following day.
Murray played mixed doubles with Serena Williams in 2019, making it to the third round, but it will be a Grand Slam debut in doubles for Raducanu.
The Scot, who has been ravaged by injuries in recent years, was asked after practice on Wednesday how the new doubles pairing had come about.
"Yesterday I was chatting to my team, they were discussing mixed and then last night I messaged her coach and just said, 'Look, do you think this is something that maybe she'd be up for doing?'" he said.
Raducanu was quick to accept the proposal from the former world number one.
"Thankfully I got quite a quick reply," said Murray. "It was quite late yesterday evening when I sent the message, it would have been after nine, so I was a bit worried she might be in bed, but I got a quick reply. She said, 'Yeah, let's do it'."
Speaking earlier this week, Raducanu, the 2021 US Open champion, said teaming up with Murray at Wimbledon was "a childhood dream".
Murray, now ranked 113th in the world, said despite his new partner's inexperience, she would be well-suited to the format.
"She's obviously unbelievably competitive and likes playing in the big stadiums and stuff with crowds so I expect she'll deal with that really well," he said.
He added: "She's a brilliant returner and great ball striker so I'd imagine she'll deal with returning guys' serves well. And, when she's getting into exchanges at the back of the court, she'll be really good."
The British pair face a tough opening contest against Marcelo Arevalo and Zhang Shuai.
El Salvador's Arevalo last month won the men's doubles title for the second time at the French Open while China's Zhang is also a two-time Grand Slam doubles champion.
Raducanu eased into the third round of the Wimbledon singles with a 6-1, 6-2 win over Elise Mertens on Wednesday.
