It's getting serious! Don Jr. takes girlfriend Kimberly Guilfoyle for first official White House event on the Fourth of July - and she even gets a handshake with the president

• Don and Kimberly have been dating since late March, around the time Trump Jr. and wife Vanessa, 40, announced their split
• Wednesday is the first time that Vanessa has been invited to join the Trumps at the White House
• She was pictured standing outside 1600 Pennsylvania Avenue, next to a smiling Don Jr. who had his hand wrapped around her waist
•  The 49-year-old later joined Don Jr.'s father, President Trump, in the Oval Office where she received a hearty handshake
• Don Jr. later later shared the photos of himself and his girlfriend meeting veterans on Instagram
• 'Today is America’s birthday, and we are making it GREAT again!' he wrote

Donald Trump Jr. has taken his new girlfriend Kimberly Guilfoyle to her first official White House event on the Fourth of July.

Don and Kimberly have been dating since late March, around the time Trump Jr. and wife Vanessa, 40, announced their split. They have since made a number of public appearances together, including at the Montana Republican Party's convention last month, and plastered pictures of themselves together all over social media. 

But Wednesday is the first time that Vanessa has been invited to join the Trumps at the White House. She was pictured standing outside 1600 Pennsylvania Avenue, next to a smiling Don Jr. who had his hand wrapped around her waist. 

Donald Trump Jr. has taken his new girlfriend Kimberly Guilfoyle to her first official White House event on the Fourth of July. She was pictured standing outside 1600 Pennsylvania Avenue, next to a smiling Don Jr. who had his hand wrapped around her waist

The 49-year-old later joined Don Jr.'s father, President Trump, in the Oval Office where she received the seal of approval from the president with a hearty handshake

The 49-year-old later joined Don Jr.'s father, President Trump, in the Oval Office where she received the seal of approval from the president with a hearty handshake.

The couple were at the White House for the Fourth of July celebrations, meeting and honoring veterans and active duty service members.

Don Jr. later shared the photos of himself and his girlfriend meeting veterans on Instagram with the caption: 'A very Happy 4th of July to everyone!

'It was great meeting all the veterans and active duty service members visiting the White House! Today is America’s birthday, and we are making it GREAT again! #fourthofjuly #weekend #usa.'

Don Jr. later shared the photos of himself and his girlfriend meeting veterans on Instagram

A source close to the president's son told DailyMail.com recently that Don Jr. and Vanessa are 'crazy about each other' and have never tried to hide their romance. 

'They're really into each other, it's obvious from the way they are together, and they haven't tried to hide it. But they haven't felt compelled to make any kind of pronouncement that they're romantically involved,' the source said. 

The source added the pair have been open about their relationship and hold hands when they are together.

The couple attended the Montana Republican Party's annual convention, where Don Jr. gave Vanessa a special shout out. The two were later seen kissing at the event.

'Just as everyone else thanks their significant others I got to thank Kimberly for coming out here. We’re going to take her fishing tomorrow then shooting,' the 40-year-old gushed. 

Don and Kimberly have been dating since late March and made a number of public appearances together, including at the Montana Republican Party's convention where the two shared a warm embrace and their first public kiss

Love birds! Kim and Don Jr have posted pictures of themselves on varying hunting and fishing trips

The couple were pictured canoodling at the new sushi restaurant at the Trump International in DC on May 31

'This is a miniature test to see if she really likes it or if she’s going to pretend to like it, but either way we’re going to have a good time or at least I will,' he joked.  

After the speech the couple were caught in a warm embrace and shared a kiss in a video Trump Jr posted on Instagram Live.

The couple also shared flicks of their outdoor adventure on Instagram and were seen smiling arm-in-arm in their fishing gear.

They also enjoyed a concert date night in Long Island, New York at a Poison gig where Don Jr couldn't help but wrap his arms around the Fox host while backstage.

He's also been spotted writing sappy comments on her pictures and fending off other men vying for his girlfriend's attention.

Don Jr and ex-wife Vanessa, 40, announced their decision to split after 12 years of marriage  on March 15.

Don and twice-divorced Kim, 49, have known each other for years but their relationship never went beyond friendship because both were married at one time or another, the source said. They are pictured above in 2008

They go way back: Kim and Vanessa were friends for years, pictured together above in 2007

Vanessa Trump attends the Easter Egg Roll on the South Lawn of the White House in Washington, Washington, D.C., U.S., on Monday, April 2, 2018

The two released a joint statement saying: 'We will always have tremendous respect for each other and our families. We have five beautiful children together and they remain our top priority. We ask for your privacy during this time.'

Vanessa has since revealed her support for her ex-husband's new relationship and asked people not to attack the new couple.

'The lengths people will go to attack a woman simply because she's dating Don. We've been separated for over 9 months and respect each other's decisions & privacy. 

'We'll focus on raising our great kids. Would be nice if the press did the same rather than obsess over our pvt lives,' she tweeted.

The soon-to-be exes appear to be on good terms and Don Jr seems to have no hesitance showing off his new relationship in the public eye.