Sarah Palin is leaping to the assistance of a fellow "mama grizzly" in Missouri.

Sarah Steelman, who has enjoyed the backing of Tea Partiers in Missouri's three-way Republican Senate primary, received Palin's endorsement earlier this month. Now, Palin is appearing in a TV ad for Steelman in the race's closing stretch.

Steelman for Senate unveiled Palin's ad on YouTube today:

Despite backing from Palin and national group Tea Party Express, Steelman, 54, is an underdog in the state's Aug. 7 primary. John Brunner, a businessman who has spent nearly $7 million of his own money on the race and who is backed by the U.S. Chamber of Commerce, leads Steelman 33 percent to 27 percent, according to a Mason-Dixon poll conducted for the St. Louis Post-Dispatch July 23-35. Rep. Todd Akin trailed in third with 17 percent.

All three Republicans lead incumbent Democratic Sen. Claire McCaskill, according to the poll.