The double time F1 world champion Alonso, to make his IndyCar debut at the Indianapolis 500 on May 28.
Button, who retired at the end of last season, is hopeful of making his mark at a venue he won at during his world title winning season with Brawn GP.
“I’m thrilled to be making a one-off return to Formula 1 racing, and I couldn’t think of a better place to make that return,” Button said in a team statement on Friday.
“I’ve won the race before, in 2009, and it’s one of my all-time favorite racetracks. It’s a tricky street circuit on which a good driver can really make a difference and, although the McLaren-Honda MCL32 hasn’t begun the season well, I think it may be more suited to Monaco than to the faster circuits.”
The Spaniard regains his cockpit for the race after Monaco — the Canadian GP on June 11, and for the remainder of the season.
Honda powered McLaren has yet to score a point after two rounds of the championship — Australia and China — following a unsatisfying campaign last year where the team struggled to adapt to the Honda engines.
“I realize we won’t have a realistic chance of repeating my 2009 victory, but I think we’ll have a opportunity to score world championship points,” said Button, who will race alongside teammate Stoffel Vandoorne.
“I was truly delighted when Jenson accepted our suggestion that he race at Monaco,” McLaren’s racing director Eric Boullier said. “Jenson is a class act. He’s a superb driver, fast, smooth and precise, and he won’t have lost any of his competitive edge over the past few months. He’ll do a great job for us, I’m sure of that.”
The Brit was widely expected to take Alonso’s seat at Monaco. Other drivers were already saying how excited they were by his potential return, even before Friday’s announcement.
“I think it would be great for the sport to have Jenson back in,” said three-time F1 champion Lewis Hamilton, who raced alongside Button at McLaren before joining Mercedes in 2012. “I like Jenson, I still think he is one of the best drivers … his caliber is still higher than any other driver who could take that spot, for sure.”
McLaren is back in the Indianapolis 500 for the first time in 38 years with Alonso’s entry, a Dallara DW12 chassis run by Andretti Autosport. Team owner Michael Andretti is a former IndyCar champion who raced in F1 for McLaren in 1993.
“I hope he’ll have some great stories to bring back to us from Indianapolis. You couldn’t get two more different racetracks than Monaco and Indy,” Boullier said.
“That’s the beauty of our sport. It also reflects the technical versatility of McLaren and Honda. And it underlines the fact that we’re racers, above everything else.”