'Full House' - the hit '80s to '90s sitcom - is back. Well, not literally, but the actors behind the very well-received show somehow took their time to gather once again to reunite for John Stamos' 50th birthday. And although the 'Full House' stars have reunited for many times in the past, this year's 'Full House' reunion is made special by Ashley Olsen's rare appearance, Yahoo! OMG! reported Thursday.

A source said that the 'Full House' actors themselves planned the Hollywood bash for John Stamos at the Sunset Tower Hotel in Hollywood on Monday, and although they were eager to surprise the actor, who turned 50 last Aug. 19, they were the ones who got shocked because of Ashley Olsen's attendance.

"Had the party of a lifetime Monday night - everyone that is so important in my life was there... Especially my mom and sisters," John Stamos posted on his Instagram account hours after the party.

Although Stamos didn't mention anything about Ashley, it was pretty obvious that the entire cast miss her and her sister Mary Kate badly.

Yahoo! stated that Mary Kate and Ashley Olsen - the twins who both portrayed the young baby of the 'Full House' family Michelle Tanner - usually find it hard to hang out with their celebrity friends and former co-stars due to their quite hectic schedule as fashion designers of their own clothing empire.

Additionally, the 27-year-olds do not really have that much to share about their past career as young actors. In a Marie Claire interview last 2010, Mary Kate was even quoted to have said that she and Ashley were like "little monkey performers" during their childhood days.

However, this time around, the Olsen twins (although Mary Kate wasn't able to attend) proved that they too long for some quality time with their long-term onscreen 'Full House' family.

Ashley Olsen was even spotted greeting her onscreen Uncle Jesse (John Stamos), and even bonded with Lori Loughlin for most of the entire duration of the party.

Lori Loughlin even tweeted a photo of her and Ashley Olsen hugging during the party, "I had a great time hanging with Ashley last night! Such a beauty inside and out."

Bob Saget hosted the fete while his daughter, Candace Cameron (now Candace Cameron Bure), who recently spotted an '80s look with Jodie Sweetin in their appearance on 'The New Hollywood Sqaures,' mingled with the crowd including Kristin Chenoweth, Daren Criss, Tom Jones, and even Priscilla Presley as well as the Beach Boys.

Candace had reportedly tweeted a photograph of the reunion with the caption, "Family Forever."

Last year, the 'Full House' actors celebrated the 25th anniversary of the show with a large cake replica of the house in the show as well as some reading sessions of the show's scripts.

Now that's how a real family gathering looks like, but perhaps we can see Mary Kate during next year's reunion?