Twenty-nine years after the Knicks acquired Doc Rivers, his son is officially going to wear the jersey, too.

The Knicks formally announced the signing of combo guard Austin Rivers in a sign-and-trade with the Rockets. The Knicks will obtain the draft rights to overseas guard Sergio Llull and forwards Tadija Dragicevic and Axel Hervelle from Houston in exchange for the draft rights to Issuf Sanon.

That’s two more bodies they can use for a future trade. For instance, if a team trades a bad contract and draft picks to the Knicks, they can use a European player to give back rather than handing over cash. NBA rules require a team to return an asset in every trade.

The Knicks agreed to terms with Rivers on Sunday, giving him a 3-year, $10 million package with the final two years not guaranteed.

Including two-way player, Jared Harper, the Knicks bring to camp six point guards.

Five players — Rivers, Elfrid Payton, Frank Ntilikina, Dennis Smith Jr. and first-round pick Immanuel Quickley — will fight for the starting job.

“He’s [the] kind of guy who’s not scared,’’ an NBA personnel man said of Rivers. “The Knicks kept a lot of games close and were competitive. Austin is the kind of guy you can trust at the end of the game and can run an offense and go 1 on 1. At times he can do too much and hurt you.’’

The 6-foot-4 Rivers, a 2012 lottery pick, has turned into something of a journeyman. Last season, Rivers averaged 8.8 points (42.1 percent FGs and 35.6 percent from 3), 2.6 rebounds and 1.7 assists over 23.4 minutes in 68 games. His father now coaches nearby for the 76ers.

There only have been two other “official” father-son Knicks tandems. Ernie Vandeweghe and Kiki Vandeweghe were the first, followed by Henry and Mike Bibby.

Patrick Ewing and Patrick Ewing Jr. and Ernie and Dan Grunfeld also wore the jersey, but the sons never played a regular-season game — just preseason. Hence, Patrick Jr. and Dan aren’t on the official all-time roster.

New coach Tom Thibodeau was on Doc Rivers’ staff in Boston and always admired his son’s basketball IQ. Doc Rivers played two-plus seasons for the Knicks — from 1992 to 1994.

There’s already speculation the Knicks will trade Rivers to his father’s Sixers at the trade deadline if they are not in the playoff race. Doc Rivers coached his son with the Clippers when Mike Woodson was there. Woodson is now a Knicks assistant.