POTW: Christina Aguilera, Jay-Z, Pink, Lil Wayne
Rihanna gets "Louder" while performing on MTV's "The Seven" in Times Square in NYC Nov. 15.

FOUR-MIDABLE: Having set the record for most No. 1s in the 18-year history of Billboard's Pop Songs radio airplay chart, Rihanna continues her winning week, lifting 2-1 on the Billboard Hot 100 with "Only Girl (In the World)" and debuting on R&B/Hip-Hop Albums at No. 1 with her fifth studio album, "Loud."

"Only Girl (In the World)" follows "What's My Name?," the Drake-assisted second single from "Loud," to the Hot 100 summit. Having banked two No. 1s previously in 2010, Rihanna becomes the first female artist in the Hot 100's 52-year archives to notch four No. 1s in a calendar year.

Here is a look at the select four acts to ascend to No. 1 on the Hot 100 at least four times in a January to December span:

The Beatles
Six, 1964: "I Want to Hold Your Hand," "She Loves You," "Can't Buy Me Love," "Love Me Do," "A Hard Day's Night," "I Feel Fine"

Four, 1965: "Eight Days a Week," "Ticket to Ride," "Help!," "Yesterday" (while the Beatles rose to No. 1 with four songs in 1965, they spent time at the top with five, as "I Feel Fine" spent the second and third weeks of its three weeks at No. 1 the weeks of Jan. 2 and 9, 1965, before collecting four more chart leaders that year).

Jackson 5
Four, 1970: "I Want You Back," "ABC," "The Love You Save"/"I Found That Girl," "I'll Be There"

Four, 2004: "Yeah!" (featuring Lil Jon and Ludacris), "Burn," "Confessions Part II," "My Boo" (Usher and Alicia Keys)

Four, 2010: "Rude Boy," "Love the Way You Lie" (Eminem featuring Rihanna), "What's My Name?" (featuring Drake), "Only Girl (In the World)"

(The Supremes did not ascend to No. 1 four times in 1965, but they did hold the No. 1 spot with four titles that year. "Come See About Me" spent the second of two weeks at No. 1 the week of Jan. 16, after first reaching No. 1 Dec. 19, 1964. The group then logged three more No. 1s in 1965: "Stop! In the Name of Love," "Back in My Arms Again" and "I Hear a Symphony."

Similarly, George Michael's "Faith" spent the last of its four weeks at No. 1 the week of Jan. 2, 1988. He added three more No. 1s that year: "Father Figure," "One More Try" and "Monkey").

Up to nine No. 1s, Rihanna enters a five-way tie for ninth place among artists with the most leaders in the Hot 100's history:

20, the Beatles
18, Mariah Carey
13, Michael Jackson
12, Madonna
12, the Supremes
11, Whitney Houston
10, Janet Jackson
10, Stevie Wonder
9, Bee Gees
9, Elton John
9, Paul McCartney
9, Rihanna
9, Usher

Since her first week atop the chart the week of May 13, 2006, with "SOS," Rihanna's nine Hot 100 No. 1s are more than twice the amount of her next closest competitor. Justin Timberlake ranks second with four No. 1s in that span.

HAPPY HOLLIDAY: Holly Holliday, that is, the newly-introduced substitute teacher at McKinley High, portrayed last Tuesday (Nov. 16) on "Glee" by Gwyneth Paltrow.

Paltrow adds vocals to the "Glee" cast's two new Hot 100 entries, a cover of Cee Lo Green's "Forget You," the chart's Hot Shot Debut at No. 11, and a mash-up of "Singin' in the Rain" and Rihanna's "Umbrella" at No. 18. (The latter entry marks the 32nd former Hot 100 No. 1 that the troupe has returned to the chart; Rihanna's original ruled for seven weeks in 2007).

With the "Glee" cast's version of "Forget You" at No. 11 and Green's original soaring to a new peak (22-9), two songs double up in the Hot 100's top 20 for a second consecutive week. Last week, the "Glee"-make of Katy Perry's "Teenage Dream" arrived at No. 8, five notches above Perry's version.

Prior to the past two weeks, two takes on a song had not shared space in the top 20 since Carrie Underwood and Bo Bice's recordings of "Inside Your Heaven" ranked in that bracket simultaneously for three frames in July 2005.

As the "Glee" cast ups its count to 95 Hot 100 appearances, second only to Elvis Presley's 108, the ensemble collects its second No. 1 on Digital Songs. "Forget You" displaces "Teenage Dream" after the latter song launched at No. 1 last week.

The "Glee" singers concurrently notch their first No. 1 on Holiday Digital Songs, as "O Holy Night" starts at the apex. The song appears on "Glee: The Music, the Christmas Album," which arrives as the cast's sixth No. 1 on the Soundtracks survey and its seventh top 10 on the Billboard 200, where it debuts at No. 8.

Paltrow not only makes her first appearances on the Hot 100, but she also rises 40-37 on Country Songs with "Country Strong," the title track from the film in which she stars with Tim McGraw, Leighton Meester and Garrett Hedlund.

Until this year, Paltrow had graced one Billboard song chart. Her Huey Lewis duet "Cruisin' " topped Adult Contemporary the week of Dec. 16, 2000. (The Academy Award winner's then-future husband, Coldplay lead singer Chris Martin, had made his Billboard chart debut three weeks earlier, when the band's introductory effort "Parachutes" first touched down on Heatseekers Albums).