Barack Obama farewell speech: When is it, how can I watch it, and what will he say?

Presidential swansong expected to include a plea to the American people to celebrate diversity and for Trump to be "more diplomatic"

Barack Obama is expected to "admonish" Donald Trump in his final speech to the nation as President (AP)

Barack Obama is expected to offer a series of “warnings” directed squarely at President-elect Donald Trump in his final address to the American people.

After eight years in the White House, Obama will deliver his swansong from his adopted home city of Chicago at 9pm local time (2am in the UK) and although details are under wraps, aides have said it will be a “serious speech” and not a “rally”.

While he is likely to offer a defence of his signature “Obamacare” health insurance reforms and his record on the economy, the headline-making part is expected to be “a series of admonitions about the challenges we face moving forward”, according to a loyalist.

These warnings from America’s first black President are likely to include a plea to Republican Mr Trump to celebrate diversity and to be more diplomatic when dealing with criticism, the unnamed aide told CNN.

Mr Trump has pledged that on his first day in office he will ask the Republican-controlled Congress to dismantle Obamacare, begin building a wall with the Mexican border and deporting illegal immigrants. He has also said he will abolish gun-free zones in schools and military bases and introduce a tough new immigration policy.

The mood of the country was very different eight years ago when Democrat Obama swept to power on a tidal wave of hope and optimism. He enjoyed high approval ratings coming into office – in contrast to Trump, who has historically the lowest approval ratings of any incoming President.

The President-elect is also expected to dramatically alter America's current diplomatic landscape by forging a close relationship with Russian President Vladimir Putin.

Mr Obama said on Sunday that he found Mr Trump “very engaging and gregarious", and that he was "not lacking in confidence”, and may have “enough craziness to think he can do the job”.

Tonight's speech will be live streamed from McCormick Place in Chicago – the first time a President has turned to his hometown to deliver his final address and just a few miles from where he made his victory speech in November 2008.

The free tickets were snapped up within half an hour of being released after thousands queued for hours in sub-zero temperatures. Organisers did not say how many tickets were available, but one aide suggested around 14,000 people will attend.

Obama is expected to be joined on stage by his wife, Michelle, who gave her own tearful farewell speech as First Lady last week, and his Vice-President Joe Biden. It is not yet known if the Obama daughters, Malia and Sasha, will join their parents.

In a statement last week, Obama said he hoped his final address would be “a chance to say thank you for this amazing journey, to celebrate the ways you’ve changed this country for the better these past eight years, and to offer some thoughts on where we all go from here”.

White House spokeswoman Jen Psaki told reporters last night: "Chicago was a natural place for him, not just because it's hometown but because it's where he got his political start, and it's where he really first learned the lesson … that it's about the actions of individuals and the actions of people, that's how real change happens."

Ms Psaki described the speech as “a passing of the baton”, a description echoed by one of Obama’s senior advisors, Valeire Jarrett, who told reporters the speech would not be “a victory lap”.

"His intention is to motivate people to want to get involved and fight for their democracy," Ms Jarrett said.

"The major focus on the speech isn't going to be reflecting back on how far we've come over the last eight years, but really looking forward and how we take the accomplishments, many (of which) through the hard work and grit of the American people came to fruition, and build on that going forward."

Obama's final Presidential speech to the public will continue a tradition set in 1796 when George Washington addressed the American people for the last time as President.

It will broadcast on networks around the world, including the BBC, and will be live streamed from the White House's website.

But Mr Obama will have another ten days at the helm, leaving office on January 20 when Donald Trump will be sworn in during his inauguration ceremony at noon.