Barack Obama and Prince Harry. Photo / Getty Images
Prince Harry's bromance with Barack Obama has fuelled rumours that the former US president and his wife Michelle will be top of the guest list when he marries Meghan Markle at Windsor Castle in May.
However, according to royal biographer Duncan Larcombe, it's extremely unlikely that the Obamas will get an invite as the couple will heed the advice of the Foreign Office not to do anything to upset diplomatic ties with the US, the Daily Mail reported.
Reports have suggested that the Foreign Office is nervous about upsetting current president Donald Trump, who has still not visited the UK in an official capacity or met the Queen.
Additionally, the royal family is supposed to remain neutral and above politics and no foreign heads of state were invited to Kate and William's wedding in 2011.
"There were religious leaders, members of the royal family, and commonwealth countries that were invited," he told townandcountry.com.
"I suspect that will be the same blueprint that Meghan and Harry will use. 'It's all very carefully orchestrated to make sure that there's no political overtones."
What might swing it for the Obamas is that Barack, 56, is, of course, no longer in office, and he and Harry, 33, do seem to have a genuine friendship.
Shortly after the engagement was announced, Mr Obama tweeted his congratulations to the couple.
He said: "We wish you a lifetime of joy and happiness together."
"I think part of their understanding is that Harry served as a soldier at the time when Obama was Commander-in-Chief," Larcombe said. "But there's a different friendship there, rather than like a business relationship."
Harry himself dodged the question of whether Mr Obama will be on the guest list or not when quizzed about it during his guest editorship of the Today programme on BBC Radio 4.
"We haven't put the invites or the guest list together yet, so who knows whether he's going to be invited or not," the British royal, 33, told BBC Radio 4's Today programme when he guest-edited the show on December 27.
"I wouldn't want to ruin that surprise."
Harry's special relationship with Barack and Michelle Obama
Obama enjoyed a hugely successful state visit to the UK in 2011, when he and his family stayed with the Queen.
Harry then struck up a rapport with Michelle Obama who he teamed up with on a number of initiatives, including offering his support to her campaigns for girls' education and better support for military families.
But he didn't meet her husband until October 2015 when the royal visited the White House for a meeting to promote the Invictus Games.
At the time, Obama warmly welcomed the prince, saying: "I've had an opportunity to spend a lot of time with so many of his family members, but this is the first time that we had a chance to talk directly."