The recent news comes following months of banter between Romney and Trump. The former Massachusetts governor gave a scathing address in March, railing on Trump and calling him a "phony," "fraud," "con man," and a "fake." Trump was quick to respond via Twitter, taking shots at Romney's failed run for the White House.
The billionaire businessman said in April that even after the nasty words they exchanged, he would not mind if Romney attended the convention.
"I don't care," Trump told the Washington Post. "He can be there if he wants."
RELATED: Twitter reactions to Romney's speech
Twitter Reacts to Romney's Speech
Mitt Romney, Bob Dole reveal plans for Republican National Convention
Ironic @MittRomney admitting that he's not the businessman @realDonaldTrump is https://t.co/J54xeyiZ4z #MakeAmericaGreatAgain #Establishment
I share my friend @MittRomney's concerns - hope American ppl think hard about who they want as Commander-in-Chief: https://t.co/yP6NqRDM17
There is a heckler now in the back of the room - he is being shouted down by the crowd. @MittRomney
You will not stop the #TrumpTrain‼️You look like a complete LOSER. Very DESPERATE attempt. #Fail https://t.co/z10jKyxAbe
Harry Reid listening to Mitt Romney go after Trump's tax returns like https://t.co/v4xqnRPXUo
Never been more proud of @MittRomney. What a speech. Morally compelling. Tactically wise. Strongly worded.
Mr @MittRomney if only YOU went after Barack Obama w/the same vigor in 2012. And to think, I campaigned for YOU. #StepAside #UlostTwice
Donald Trump, Don't Take the Bait
The "machine's" deception and nonsensical attack on Trump isn't really an... https://t.co/XkLVBlZJhh
Well said, @MittRomney. -John https://t.co/pTwmBTaeAo
In essence, is Mitt calling Trump supporters…what’s the word….stupid?
Sending Mitt Romney out to attack Trump will only further galvanize his supporters. It also makes sets them up for a divisive spring battle.
@MittRomney political indictment of @realDonaldTrump was the clarion call the #GOPEstablishment needed but one the GOP base does not want.
A brilliant speech by @MittRomney. No one can ever question his love for our party and our country. #TrueLeadership #MittRomney
.@MittRomney not holding back; unloading the full load on @realDonaldTrump. I bet the Donald is reflecting on his critique right now!
The lack of loyalty is truly astonishing. #Romney https://t.co/wIrpD3DzMH
@MittRomney speaks the truth. Our country deserves better than a crass bully who admires thugs like Putin. #NeverTrump #TeamMarco
During his campaign, Trump has taken jabs at George W. Bush for his mishandling of the 9/11 attacks. Spokespeople for the Bushes stated this week that they both are still opting to not endorse a candidate, even though only Trump remains.