Elton John's son Zachary high-fived Bono as he helped out at the 'Rocket Man' singer's 21^st Annual Academy Awards Viewing Party and Benefit on Sunday to raise money for HIV and Aids research.

Elton John's son wasn't the only one doing 'high-fives' recently; Elton John himself reportedly slapped the Lumineers's drummer during the Grammy's a few weeks ago. 

Sir Elton John and his husband David Furnish showed off their two-year-old son Zachary to celebrity guests at this past weekend's star-studded benefit.

The Oscars viewing party is held annually to raise money for John's charity, the Elton John AIDS Foundation.

Over the past 20 years, the event has raised nearly $34 million for HIV and Aids research.

Sir Elton John explained on the Oscars red carpet how the money helps victims of the devastating health condition, "The thing is, it's a very treatable disease now. We've come so far medically that you can treat the disease and it's easier than diabetes."

He continued, "It's much simpler and people shouldn't have that stigma, but we need to have more compassion from people for one another."

This was Zachary's first time attending the post-Oscars fundraiser bash. He was considered the guest of honor at the annual event.  

Zachary was dressed in a black tuxedo, bow tie and white trainers, and was given attention by U2 front man Bono. He was rewarded for his attentions when Zachary gave Bono a high-five.

John and Furnish insisted that they didn't let Zachary or his brother stay up past their bedtimes.

Sir Elton John has another son, newborn Elijah, who stayed home with the babysitters. Zachary's new brother was born to a surrogate mother last month.

According to MSN David commented at the event, "We'll make sure they get home in time for their regular bath time and story time with the nanny. Then we'll see them tomorrow morning, when we get back." 

In addition to Bono, Kim and Kourtney Kardashian appeared at the party talking to Miley Cyrus and Kelly Osbourne.

Elton John was also photographed talking with rapper Chris Brown and Aerosmith's Steven Tyler. 

One star who was not mentioned at party was Lumineer's drummer, Jeremiah Fraites. 

Elton John reportedly slapped the drummer at the Grammy Awards this month, according to Entertainment Weekly.

In an interview, the band's Wesley Shultz revealed, "We were nominated for two awards but didn't win. As we were walking in Elton John stopped us and said he has been listening to our album and was a fan. Our drummer said, 'There's no f-ing way you are a fan!' Elton just slapped him in the face and put him straight. It was a special moment."