STORY: TRUMP: "I just want to say that I have invited Biden to debate. He can do it any time he wants, including tonight."
BIDEN: "Well, make my day, pal. I'll even do it twice."
U.S. President Joe Biden and Republican rival Donald Trump have agreed to face off in two debates for the presidential election.
Tens of millions of Americans will be tuning in live...
And it'll be high risk for both sides - in a tight race with low enthusiasm from voters.
Here's what you need to know.
:: The Biden-Trump debates: what you need to know
CNN will host the first debate on June 27 in their Atlanta studio with no audience.
The event will be moderated by anchors Jake Tapper and Dana Bash.
ABC will host the second debate on September 10.
The two presidential hopefuls are already debating some ground rules.
:: The rules
Trump - who refused to debate his rivals during the Republican nominating race - has been pushing Biden for months to agree to the debates.
Biden has now said he'll participate in two debates under strict rules to reduce interruptions.
Trump wants more than two debates... and a very large venue "for excitement purposes."
He has said they should be two hours in length and that both men should be required to stand.
:: The risks
The move to accept debates shows Biden is willing to take a calculated risk to boost his opinion poll numbers in a race in which he is trailing Trump in key battleground states.
Biden aides think debates could hurt Trump by exposing his positions on issues -- like abortion -- that they see as political vulnerabilities.
BIDEN: "Putin may circle Kyiv with tanks, but he'll never gain the hearts and souls of the Iranian people."
Trump aides see Biden as prone to verbal slip-ups that could amplify voter concerns about the 81-year-old president's age.
Trump himself will be 78 by the time the first debate is held.
