Dream promoters announced an additional two bouts to their June 15 event at the Yokohama Arena in Kanagawa, Japan. In a special-rules submission grappling match, Pride's 2006 open-weight grand prix champion Mirko "Cro Cop" Filipovic will test his ground skills against Ralek Gracie (Pictures), the son of UFC founder Rorion Gracie at Dream 4.

The bout will be held under modified rules, set for two five-minute rounds with no points system. The winner can only be determined only by a successful submission and if it goes the distance, the fight will automatically be declared a draw.

California native Gracie, 22, was recently awarded his black belt in Brazilian jiu-jitsu and won his first and only MMA fight to date, an easy first round submission over Japanese pro wrestler Katsuyori Shibata (Pictures), last July at K-1 Hero's Middleweight Tournament Opening Round, also in Yokohama.

Gracie had also been considered as opponent for Melvin Manhoef (Pictures) in the middleweight tournament's alternate bout, but in the end Korean judoka Dae Won Kim (Pictures) got the contract.

"I expect to win by submission in the first round and that's an upside to me," Gracie told Sherdog.com.

Filipovic was also enthusiastic about the fight on his personal Web site blog.

"This is probably something you didn't see coming, it came really out of blue," Filipovic wrote. "However, under the given circumstances, this is a unique opportunity for me to test my ground game against top level competition and it's going to be exciting! I'll prepare for this match with my grappling coach Marcio Corletta, a two-time world champion."

Filipovic was originally proposed a fight against fellow kickboxing champion Jerome LeBanner (Pictures) under MMA rules. However, the Frenchman asked to postpone the bout because he also had an offer to fight Semmy Schilt (Pictures) for the K-1 super heavyweight title just two weeks after the planned encounter with Filipovic.

While hardcore fans of the Croatian knockout artist will certainly frown at the notion of their hero participating in a grappling exhibition, Filipovic's decision to compete is understandable. Aside from a 56-second cameo appearance against overwhelmed Japanese grappler Tatsuya Mizuno (Pictures) last March at Dream 1, the Zagreb native has not competed in a Japanese ring for over seventeen months.

Filipovic posted a disappointing 1-2 record in the UFC in 2007, before returning in 2008 to the country where he earned a reputation as one of the sport's fiercest strikers.

A second fight was also announced for Dream's newly established featherweight division. Hero's star Hideo Tokoro (Pictures) will make his promotional debut against American grappler Darren Uyenoyama (Pictures). This came as a surprise to many insiders of the Japanese fight scene, because Tokoro is a protégé of Akira Maeda (Pictures), who had been ousted by his fellow FEG executives -- who make up part of the Dream promotional team -- earlier this year.

On the heels of the gripping featherweight battle between Shoji Maruyama (Pictures) and Takeshi Yamazaki (Pictures) at Dream 3, this scrap could be another attempt at finding a future challenger for FEG's Japanese superstar Norifumi "Kid" Yamamoto.